diff --git a/subsys/net/lib/lwm2m/lwm2m_object.h b/subsys/net/lib/lwm2m/lwm2m_object.h
index 170a99c023d..26322f50b1b 100644
--- a/subsys/net/lib/lwm2m/lwm2m_object.h
+++ b/subsys/net/lib/lwm2m/lwm2m_object.h
@@ -251,7 +251,7 @@ struct lwm2m_engine_obj {
 		if (_ri_ptr != NULL && _ri_count > 0) { \
 			for (int _i = 0; _i < _ri_count; _i++) { \
 				_ri_ptr[_ri_idx + _i].data_ptr = \
-						(_data_ptr + _i); \
+						((uint8_t *) _data_ptr + (_i * _data_sz)); \
 				_ri_ptr[_ri_idx + _i].max_data_len = \
 						_data_sz; \
 				_ri_ptr[_ri_idx + _i].data_len = \
diff --git a/tests/net/lib/lwm2m/lwm2m_registry/prj.conf b/tests/net/lib/lwm2m/lwm2m_registry/prj.conf
index 84e3a4bb289..223f97a0762 100644
--- a/tests/net/lib/lwm2m/lwm2m_registry/prj.conf
+++ b/tests/net/lib/lwm2m/lwm2m_registry/prj.conf
@@ -13,3 +13,4 @@ CONFIG_LWM2M_IPSO_TEMP_SENSOR_VERSION_1_1=y
 CONFIG_LWM2M_IPSO_TEMP_SENSOR_INSTANCE_COUNT=4
 CONFIG_LWM2M_CONN_MON_OBJ_SUPPORT=y
 CONFIG_LWM2M_CONNMON_OBJECT_VERSION_1_2=y
+CONFIG_LWM2M_PORTFOLIO_OBJ_SUPPORT=y
diff --git a/tests/net/lib/lwm2m/lwm2m_registry/src/lwm2m_registry.c b/tests/net/lib/lwm2m/lwm2m_registry/src/lwm2m_registry.c
index d847b5a35cd..d4c0a7757a6 100644
--- a/tests/net/lib/lwm2m/lwm2m_registry/src/lwm2m_registry.c
+++ b/tests/net/lib/lwm2m/lwm2m_registry/src/lwm2m_registry.c
@@ -285,6 +285,42 @@ ZTEST(lwm2m_registry, test_resource_instance_creation_and_deletion)
 	zassert_equal(ret, 0);
 }
 
+ZTEST(lwm2m_registry, test_resource_instance_strings)
+{
+	int ret;
+	char buf[256] = {0};
+	static const char string_a[] = "Hello";
+	static const char string_b[] = "World";
+	struct lwm2m_obj_path path_a = LWM2M_OBJ(16, 0, 0, 0);
+	struct lwm2m_obj_path path_b = LWM2M_OBJ(16, 0, 0, 1);
+
+	ret = lwm2m_create_object_inst(&LWM2M_OBJ(16, 0));
+	zassert_equal(ret, 0);
+
+	ret = lwm2m_create_res_inst(&path_a);
+	zassert_equal(ret, 0);
+
+	ret = lwm2m_create_res_inst(&path_b);
+	zassert_equal(ret, 0);
+
+	ret = lwm2m_set_string(&path_a, string_a);
+	zassert_equal(ret, 0);
+
+	ret = lwm2m_set_string(&path_b, string_b);
+	zassert_equal(ret, 0);
+
+	ret = lwm2m_get_string(&path_a, buf, sizeof(buf));
+	zassert_equal(ret, 0);
+	zassert_equal(0, memcmp(buf, string_a, sizeof(string_a)));
+
+	ret = lwm2m_get_string(&path_b, buf, sizeof(buf));
+	zassert_equal(ret, 0);
+	zassert_equal(0, memcmp(buf, string_b, sizeof(string_b)));
+
+	ret = lwm2m_delete_object_inst(&LWM2M_OBJ(16, 0));
+	zassert_equal(ret, 0);
+}
+
 ZTEST(lwm2m_registry, test_callbacks)
 {
 	int ret;