diff --git a/src/ol/geom/multipoint.js b/src/ol/geom/multipoint.js
index 54c7a8e170..19326bd8ed 100644
--- a/src/ol/geom/multipoint.js
+++ b/src/ol/geom/multipoint.js
@@ -2,6 +2,7 @@ goog.provide('ol.geom.MultiPoint');
 
 goog.require('goog.array');
 goog.require('goog.asserts');
+goog.require('ol.array');
 goog.require('ol.extent');
 goog.require('ol.geom.GeometryType');
 goog.require('ol.geom.Point');
@@ -34,7 +35,7 @@ ol.geom.MultiPoint.prototype.appendPoint = function(point) {
   if (goog.isNull(this.flatCoordinates)) {
     this.flatCoordinates = point.getFlatCoordinates().slice();
   } else {
-    goog.array.extend(this.flatCoordinates, point.getFlatCoordinates());
+    ol.array.safeExtend(this.flatCoordinates, point.getFlatCoordinates());
   }
   this.dispatchChangeEvent();
 };