diff --git a/jerry-core/ecma/base/ecma-property-hashmap.c b/jerry-core/ecma/base/ecma-property-hashmap.c
index 2c1634f1e..ed3b1db9b 100644
--- a/jerry-core/ecma/base/ecma-property-hashmap.c
+++ b/jerry-core/ecma/base/ecma-property-hashmap.c
@@ -300,13 +300,8 @@ ecma_property_hashmap_insert (ecma_object_t *object_p, /**< object */
   bits_p += (entry_index >> 3);
   mask = (uint32_t) (1 << (entry_index & 0x7));
 
-  if (!(*bits_p & mask))
-  {
-    /* Deleted entries also has ECMA_NULL_POINTER
-     * value, but they are not NULL values. */
-    hashmap_p->null_count--;
-    JERRY_ASSERT (hashmap_p->null_count > 0);
-  }
+  hashmap_p->null_count--;
+  JERRY_ASSERT (hashmap_p->null_count > 0);
 
   if (property_index == 0)
   {
@@ -338,6 +333,22 @@ ecma_property_hashmap_delete (ecma_object_t *object_p, /**< object */
 
   JERRY_ASSERT (hashmap_p->header.types[0] == ECMA_PROPERTY_TYPE_HASHMAP);
 
+  hashmap_p->null_count++;
+
+  /* The NULLs are above 3/4 of the hashmap. */
+  if (hashmap_p->null_count > ((hashmap_p->max_property_count * 3) >> 2))
+  {
+    uint32_t max_property_count = hashmap_p->max_property_count;
+
+    ecma_property_hashmap_free (object_p);
+
+    if (max_property_count >= ECMA_PROPERTY_HASMAP_MINIMUM_SIZE * 2)
+    {
+      ecma_property_hashmap_create (object_p);
+    }
+    return;
+  }
+
   uint32_t entry_index = ecma_string_get_property_name_hash (*property_p, name_cp);
   uint32_t step = ecma_property_hashmap_steps[entry_index & (ECMA_PROPERTY_HASHMAP_NUMBER_OF_STEPS - 1)];
   uint32_t mask = hashmap_p->max_property_count - 1;
diff --git a/tests/jerry/regression-test-issue-1533.js b/tests/jerry/regression-test-issue-1533.js
new file mode 100644
index 000000000..3b77ec50f
--- /dev/null
+++ b/tests/jerry/regression-test-issue-1533.js
@@ -0,0 +1,26 @@
+// Copyright JS Foundation and other contributors, http://js.foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+var a = [];
+
+for (var i = 0; i < 200; ++i)
+  a[i] = 5;
+
+for (var i = 0; i < 200; ++i)
+  a[i] = a[i] + 5;
+
+for (var i = 0; i < 200; ++i)
+  delete a[i]
+
+a[0] = 5