diff --git a/mod/assignment/lib.php b/mod/assignment/lib.php
index f698054aca0..e3fca57c430 100644
--- a/mod/assignment/lib.php
+++ b/mod/assignment/lib.php
@@ -1922,8 +1922,12 @@ class assignment_base {
                     $button->set_format_by_file($file);
                     $output .= $button->to_html(PORTFOLIO_ADD_ICON_LINK);
                 }
-                $output .= plagiarism_get_links(array('userid'=>$userid, 'file'=>$file, 'cmid'=>$this->cm->id, 'course'=>$this->course, 'assignment'=>$this->assignment));
-                $output .= '<br />';
+                
+                if ($CFG->enableplagiarism) {
+                    require_once($CFG->libdir.'/plagiarismlib.php');
+                    $output .= plagiarism_get_links(array('userid'=>$userid, 'file'=>$file, 'cmid'=>$this->cm->id, 'course'=>$this->course, 'assignment'=>$this->assignment));
+                    $output .= '<br />';
+                }
             }
             if ($CFG->enableportfolios && count($files) > 1  && $this->portfolio_exportable() && has_capability('mod/assignment:exportownsubmission', $this->context)) {
                 $button->set_callback_options('assignment_portfolio_caller', array('id' => $this->cm->id, 'submissionid' => $submission->id), '/mod/assignment/locallib.php');