diff --git a/source/MAC/IEEE802_15_4/mac_mcps_sap.c b/source/MAC/IEEE802_15_4/mac_mcps_sap.c
index 086de4503474..22b8061c8819 100644
--- a/source/MAC/IEEE802_15_4/mac_mcps_sap.c
+++ b/source/MAC/IEEE802_15_4/mac_mcps_sap.c
@@ -2351,12 +2351,6 @@ void mcps_sap_pre_parsed_frame_buffer_free(mac_pre_parsed_frame_t *buf)
 
 mac_pre_parsed_frame_t *mcps_sap_pre_parsed_frame_buffer_get(const uint8_t *data_ptr, uint16_t frame_length)
 {
-    // check that system has enough space to handle the new packet
-    if (!ns_monitor_packet_allocation_allowed()) {
-        // stack can not handle new packets for routing
-        return NULL;
-    }
-
     mac_pre_parsed_frame_t *buffer = ns_dyn_mem_temporary_alloc(sizeof(mac_pre_parsed_frame_t) + frame_length);
 
     if (buffer) {
diff --git a/source/MAC/IEEE802_15_4/mac_pd_sap.c b/source/MAC/IEEE802_15_4/mac_pd_sap.c
index 54669e879451..799205ceb0e2 100644
--- a/source/MAC/IEEE802_15_4/mac_pd_sap.c
+++ b/source/MAC/IEEE802_15_4/mac_pd_sap.c
@@ -36,6 +36,7 @@
 #include "MAC/IEEE802_15_4/mac_mcps_sap.h"
 #include "MAC/IEEE802_15_4/mac_cca_threshold.h"
 #include "MAC/rf_driver_storage.h"
+#include "Core/include/ns_monitor.h"
 #include "ns_trace.h"
 
 #define TRACE_GROUP "mPDs"
@@ -904,11 +905,17 @@ static int8_t mac_pd_sap_generate_edfe_response(protocol_interface_rf_mac_setup_
 
 static mac_pre_parsed_frame_t *mac_pd_sap_allocate_receive_buffer(protocol_interface_rf_mac_setup_s *rf_ptr, const mac_fcf_sequence_t *fcf_read, arm_pd_sap_generic_ind_t *pd_data_ind)
 {
+    // Unless receiving Ack, check that system has enough space to handle the new packet
+    if (fcf_read->frametype != FC_ACK_FRAME) {
+        if (!ns_monitor_packet_allocation_allowed()) {
+            // stack can not handle new packets for routing
+            return NULL;
+        }
+    }
     mac_pre_parsed_frame_t *buffer = mcps_sap_pre_parsed_frame_buffer_get(pd_data_ind->data_ptr, pd_data_ind->data_len);
     if (!buffer) {
         return NULL;
     }
-
     //Copy Pre Parsed values
     buffer->fcf_dsn = *fcf_read;
     buffer->timestamp = mac_pd_sap_get_phy_rx_time(rf_ptr);
diff --git a/test/nanostack/unittest/mac/mac_mcps_sap/test_mac_mcps_sap.c b/test/nanostack/unittest/mac/mac_mcps_sap/test_mac_mcps_sap.c
index cc72f50549d8..9508acf6e153 100644
--- a/test/nanostack/unittest/mac/mac_mcps_sap/test_mac_mcps_sap.c
+++ b/test/nanostack/unittest/mac/mac_mcps_sap/test_mac_mcps_sap.c
@@ -2194,26 +2194,6 @@ bool test_mcps_sap_pre_parsed_frame_buffer_get()
     if (memcmp(mac_header_message_start_pointer(buf), buffer, 8) != 0) {
         return false;
     }
-    ns_dyn_mem_free(buf);
-
-    // Test that if dynamic memory is low, then allocation fails
-    nsdynmemlib_stub.returnCounter = 1;
-    ns_monitor_stub.return_bool = false;
-
-    buf = mcps_sap_pre_parsed_frame_buffer_get(buffer, 8);
-    if (buf) {
-        return false;
-    }
-
-    // Test that allocation succeeds when there is enough heap
-    nsdynmemlib_stub.returnCounter = 1;
-    ns_monitor_stub.return_bool = true;
-
-    buf = mcps_sap_pre_parsed_frame_buffer_get(buffer, 8);
-    if (!buf || buf->frameLength != 8) {
-        return false;
-    }
-
     ns_dyn_mem_free(buf);
     return true;
 }
diff --git a/test/nanostack/unittest/mac/mac_pd_sap/Makefile b/test/nanostack/unittest/mac/mac_pd_sap/Makefile
index 41e17bb44cba..e9dd6cd02d76 100644
--- a/test/nanostack/unittest/mac/mac_pd_sap/Makefile
+++ b/test/nanostack/unittest/mac/mac_pd_sap/Makefile
@@ -27,6 +27,7 @@ TEST_SRC_FILES = \
         ../../stub/buffer_dyn_stub.c \
         ../../stub/fhss_config_stub.c \
         ../../stub/sw_mac_stub.c \
+        ../../stub/ns_monitor_stub.c \
 
 include ../../MakefileWorker.mk
 
diff --git a/test/nanostack/unittest/mac/mac_pd_sap/test_mac_pd_sap.c b/test/nanostack/unittest/mac/mac_pd_sap/test_mac_pd_sap.c
index 713fcfc5a73c..a217e6206c71 100644
--- a/test/nanostack/unittest/mac/mac_pd_sap/test_mac_pd_sap.c
+++ b/test/nanostack/unittest/mac/mac_pd_sap/test_mac_pd_sap.c
@@ -33,6 +33,7 @@
 #include "nsdynmemLIB_stub.h"
 #include "fhss_config_stub.h"
 #include "sw_mac_stub.h"
+#include "ns_monitor_stub.h"
 #include <string.h>
 
 static int8_t tx_return = -1;
@@ -438,7 +439,29 @@ bool test_mac_pd_sap_data_cb()
         return false;
     }
 
+    // Test when ns monitor don't allow reception
+    ns_monitor_stub.return_bool = false;
+    mac_mcps_sap_stub.pre_parsed = frame_buf;
+    nsdynmemlib_stub.returnCounter = 2;
+    fcf.frametype = FC_DATA_FRAME;
+    mac_header_helper_functions_stub.fcf = fcf;
+    phy_message.message.generic_data_ind.data_len = 32;
+    ret = mac_pd_sap_data_cb(&rf_ptr, &phy_message);
+    if (ret != -3) {
+        return false;
+    }
 
+    // Test when ns monitor allows Ack reception
+    ns_monitor_stub.return_bool = false;
+    mac_mcps_sap_stub.pre_parsed = frame_buf;
+    nsdynmemlib_stub.returnCounter = 2;
+    fcf.frametype = FC_ACK_FRAME;
+    mac_header_helper_functions_stub.fcf = fcf;
+    phy_message.message.generic_data_ind.data_len = 32;
+    ret = mac_pd_sap_data_cb(&rf_ptr, &phy_message);
+    if (ret != -1) {
+        return false;
+    }
 
     //Test MAC15_4_PD_SAP_DATA_TX_CONFIRM
     phy_message.id = MAC15_4_PD_SAP_DATA_TX_CONFIRM;