diff --git a/tests/suites/test_suite_psa_crypto.function b/tests/suites/test_suite_psa_crypto.function
index b605c68333..63a65a1a16 100644
--- a/tests/suites/test_suite_psa_crypto.function
+++ b/tests/suites/test_suite_psa_crypto.function
@@ -4615,7 +4615,8 @@ void cipher_verify_output_multipart(int alg_arg,
     PSA_ASSERT(psa_cipher_update(&operation1,
                                  input->x + first_part_size,
                                  input->len - first_part_size,
-                                 output1, output1_buffer_size,
+                                 output1 + output1_length,
+                                 output1_buffer_size - output1_length,
                                  &function_output_length));
     TEST_LE_U(function_output_length,
               PSA_CIPHER_UPDATE_OUTPUT_SIZE(key_type,
@@ -4661,7 +4662,8 @@ void cipher_verify_output_multipart(int alg_arg,
     PSA_ASSERT(psa_cipher_update(&operation2,
                                  output1 + first_part_size,
                                  output1_length - first_part_size,
-                                 output2, output2_buffer_size,
+                                 output2 + output2_length,
+                                 output2_buffer_size - output2_length,
                                  &function_output_length));
     TEST_LE_U(function_output_length,
               PSA_CIPHER_UPDATE_OUTPUT_SIZE(key_type,