diff --git a/include/microkernel.h b/include/microkernel.h
index 2bcd137e1c7..3468b947381 100644
--- a/include/microkernel.h
+++ b/include/microkernel.h
@@ -63,8 +63,6 @@ extern "C" {
 #define MON_EVENT 8
 #define MON_ALL 15
 
-extern void _task_nop(void);
-
 extern int task_offload_to_fiber(int (*)(), void *);
 
 /* The following two typedefs are used in kernel_main.c */
diff --git a/samples/microkernel/benchmark/app_kernel/src/nop_b.c b/samples/microkernel/benchmark/app_kernel/src/nop_b.c
index 521a0db0c97..61e25b322d6 100644
--- a/samples/microkernel/benchmark/app_kernel/src/nop_b.c
+++ b/samples/microkernel/benchmark/app_kernel/src/nop_b.c
@@ -34,6 +34,10 @@
 
 #ifdef MICROKERNEL_CALL_BENCH
 
+/* utilize non-public microkernel API for test purposes */
+
+extern void _task_nop(void);
+
 /*******************************************************************************
  *
  * call_test - Kernel entry timing test