diff --git a/jerry-core/ecma/base/ecma-property-hashmap.c b/jerry-core/ecma/base/ecma-property-hashmap.c
index e9032a8a1..97c3fd234 100644
--- a/jerry-core/ecma/base/ecma-property-hashmap.c
+++ b/jerry-core/ecma/base/ecma-property-hashmap.c
@@ -138,6 +138,7 @@ ecma_property_hashmap_create (ecma_object_t *object_p) /**< object */
   hashmap_p->header.next_property_cp = object_p->property_list_or_bound_object_cp;
   hashmap_p->max_property_count = max_property_count;
   hashmap_p->null_count = max_property_count - named_property_count;
+  hashmap_p->unused_count = max_property_count - named_property_count;
 
   jmem_cpointer_t *pair_list_p = (jmem_cpointer_t *) (hashmap_p + 1);
   uint8_t *bits_p = (uint8_t *) (pair_list_p + max_property_count);
@@ -312,6 +313,9 @@ ecma_property_hashmap_insert (ecma_object_t *object_p, /**< object */
   hashmap_p->null_count--;
   JERRY_ASSERT (hashmap_p->null_count > 0);
 
+  hashmap_p->unused_count--;
+  JERRY_ASSERT (hashmap_p->unused_count > 0);
+
   if (property_index == 0)
   {
     *bits_p = (uint8_t) ((*bits_p) & ~mask);
@@ -345,10 +349,10 @@ 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++;
+  hashmap_p->unused_count++;
 
   /* The NULLs are above 3/4 of the hashmap. */
-  if (hashmap_p->null_count > ((hashmap_p->max_property_count * 3) >> 2))
+  if (hashmap_p->unused_count > ((hashmap_p->max_property_count * 3) >> 2))
   {
     return ECMA_PROPERTY_HASHMAP_DELETE_RECREATE_HASHMAP;
   }
diff --git a/jerry-core/ecma/base/ecma-property-hashmap.h b/jerry-core/ecma/base/ecma-property-hashmap.h
index 3ad4dbbd0..02d11a2a1 100644
--- a/jerry-core/ecma/base/ecma-property-hashmap.h
+++ b/jerry-core/ecma/base/ecma-property-hashmap.h
@@ -36,6 +36,7 @@ typedef struct
   ecma_property_header_t header; /**< header of the property */
   uint32_t max_property_count; /**< maximum property count (power of 2) */
   uint32_t null_count; /**< number of NULLs in the map */
+  uint32_t unused_count; /**< number of unused entires in the map */
 
   /*
    * The hash is followed by max_property_count ecma_cpointer_t
diff --git a/tests/jerry/regression-test-issue-1552.js b/tests/jerry/regression-test-issue-1552.js
new file mode 100644
index 000000000..9e1a6875e
--- /dev/null
+++ b/tests/jerry/regression-test-issue-1552.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 o = []
+
+function add(i)
+{
+  delete o[i & 31];
+  o[i] = 0;
+}
+
+for (var i = 0; i < 130; i++)
+{
+  add(i)
+}