diff --git a/course/changenumsections.php b/course/changenumsections.php
index deed3670e85..beeaea930bf 100644
--- a/course/changenumsections.php
+++ b/course/changenumsections.php
@@ -52,8 +52,8 @@ if (isset($courseformatoptions['numsections'])) {
     // Don't go less than 0, intentionally redirect silently (for the case of
     // double clicks).
     if ($courseformatoptions['numsections'] >= 0) {
-        course_get_format($course)->update_course_format_options(
-                array('numsections' => $courseformatoptions['numsections']));
+        update_course((object)array('id' => $course->id,
+            'numsections' => $courseformatoptions['numsections']));
     }
 }
 
diff --git a/course/format/topics/lib.php b/course/format/topics/lib.php
index f5a8067f7fb..034b58e00c2 100644
--- a/course/format/topics/lib.php
+++ b/course/format/topics/lib.php
@@ -315,8 +315,8 @@ class format_topics extends format_base {
      */
     public function update_course_format_options($data, $oldcourse = null) {
         global $DB;
+        $data = (array)$data;
         if ($oldcourse !== null) {
-            $data = (array)$data;
             $oldcourse = (array)$oldcourse;
             $options = $this->course_format_options();
             foreach ($options as $key => $unused) {
@@ -337,7 +337,19 @@ class format_topics extends format_base {
                 }
             }
         }
-        return $this->update_format_options($data);
+        $changed = $this->update_format_options($data);
+        if ($changed && array_key_exists('numsections', $data)) {
+            // If the numsections was decreased, try to completely delete the orphaned sections (unless they are not empty).
+            $numsections = (int)$data['numsections'];
+            $maxsection = $DB->get_field_sql('SELECT max(section) from {course_sections}
+                        WHERE course = ?', array($this->courseid));
+            for ($sectionnum = $maxsection; $sectionnum > $numsections; $sectionnum--) {
+                if (!$this->delete_section($sectionnum, false)) {
+                    break;
+                }
+            }
+        }
+        return $changed;
     }
 
     /**
diff --git a/course/format/topics/tests/format_topics_test.php b/course/format/topics/tests/format_topics_test.php
new file mode 100644
index 00000000000..09dea51a6cd
--- /dev/null
+++ b/course/format/topics/tests/format_topics_test.php
@@ -0,0 +1,64 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * format_topics related unit tests
+ *
+ * @package    format_topics
+ * @copyright  2015 Marina Glancy
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+global $CFG;
+require_once($CFG->dirroot . '/course/lib.php');
+
+/**
+ * format_topics related unit tests
+ *
+ * @package    format_topics
+ * @copyright  2015 Marina Glancy
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class format_topics_testcase extends advanced_testcase {
+
+    public function test_update_course_numsections() {
+        global $DB;
+        $this->resetAfterTest(true);
+
+        $generator = $this->getDataGenerator();
+
+        $course = $generator->create_course(array('numsections' => 10, 'format' => 'topics'),
+            array('createsections' => true));
+        $generator->create_module('assign', array('course' => $course, 'section' => 7));
+
+        $this->setAdminUser();
+
+        $this->assertEquals(11, $DB->count_records('course_sections', array('course' => $course->id)));
+
+        // Change the numsections to 8, last two sections did not have any activities, they should be deleted.
+        update_course((object)array('id' => $course->id, 'numsections' => 8));
+        $this->assertEquals(9, $DB->count_records('course_sections', array('course' => $course->id)));
+        $this->assertEquals(9, count(get_fast_modinfo($course)->get_section_info_all()));
+
+        // Change the numsections to 5, section 8 should be deleted but section 7 should remain as it has activities.
+        update_course((object)array('id' => $course->id, 'numsections' => 6));
+        $this->assertEquals(8, $DB->count_records('course_sections', array('course' => $course->id)));
+        $this->assertEquals(8, count(get_fast_modinfo($course)->get_section_info_all()));
+        $this->assertEquals(6, course_get_format($course)->get_course()->numsections);
+    }
+}
diff --git a/course/format/weeks/lib.php b/course/format/weeks/lib.php
index 1e472d1f134..59a58b302f2 100644
--- a/course/format/weeks/lib.php
+++ b/course/format/weeks/lib.php
@@ -324,8 +324,8 @@ class format_weeks extends format_base {
      */
     public function update_course_format_options($data, $oldcourse = null) {
         global $DB;
+        $data = (array)$data;
         if ($oldcourse !== null) {
-            $data = (array)$data;
             $oldcourse = (array)$oldcourse;
             $options = $this->course_format_options();
             foreach ($options as $key => $unused) {
@@ -346,7 +346,19 @@ class format_weeks extends format_base {
                 }
             }
         }
-        return $this->update_format_options($data);
+        $changed = $this->update_format_options($data);
+        if ($changed && array_key_exists('numsections', $data)) {
+            // If the numsections was decreased, try to completely delete the orphaned sections (unless they are not empty).
+            $numsections = (int)$data['numsections'];
+            $maxsection = $DB->get_field_sql('SELECT max(section) from {course_sections}
+                        WHERE course = ?', array($this->courseid));
+            for ($sectionnum = $maxsection; $sectionnum > $numsections; $sectionnum--) {
+                if (!$this->delete_section($sectionnum, false)) {
+                    break;
+                }
+            }
+        }
+        return $changed;
     }
 
     /**
diff --git a/course/format/weeks/tests/format_weeks_test.php b/course/format/weeks/tests/format_weeks_test.php
new file mode 100644
index 00000000000..a388b59706e
--- /dev/null
+++ b/course/format/weeks/tests/format_weeks_test.php
@@ -0,0 +1,64 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * format_weeks related unit tests
+ *
+ * @package    format_weeks
+ * @copyright  2015 Marina Glancy
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+global $CFG;
+require_once($CFG->dirroot . '/course/lib.php');
+
+/**
+ * format_weeks related unit tests
+ *
+ * @package    format_weeks
+ * @copyright  2015 Marina Glancy
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+class format_weeks_testcase extends advanced_testcase {
+
+    public function test_update_course_numsections() {
+        global $DB;
+        $this->resetAfterTest(true);
+
+        $generator = $this->getDataGenerator();
+
+        $course = $generator->create_course(array('numsections' => 10, 'format' => 'weeks'),
+            array('createsections' => true));
+        $generator->create_module('assign', array('course' => $course, 'section' => 7));
+
+        $this->setAdminUser();
+
+        $this->assertEquals(11, $DB->count_records('course_sections', array('course' => $course->id)));
+
+        // Change the numsections to 8, last two sections did not have any activities, they should be deleted.
+        update_course((object)array('id' => $course->id, 'numsections' => 8));
+        $this->assertEquals(9, $DB->count_records('course_sections', array('course' => $course->id)));
+        $this->assertEquals(9, count(get_fast_modinfo($course)->get_section_info_all()));
+
+        // Change the numsections to 5, section 8 should be deleted but section 7 should remain as it has activities.
+        update_course((object)array('id' => $course->id, 'numsections' => 6));
+        $this->assertEquals(8, $DB->count_records('course_sections', array('course' => $course->id)));
+        $this->assertEquals(8, count(get_fast_modinfo($course)->get_section_info_all()));
+        $this->assertEquals(6, course_get_format($course)->get_course()->numsections);
+    }
+}