diff --git a/src/ska/base/state_machine.py b/src/ska/base/state_machine.py
index 0dc1f325762e29d9da711c10346197263adeb73c..5c5104a3646ae21f0929365355bc9e7c64d4d353 100644
--- a/src/ska/base/state_machine.py
+++ b/src/ska/base/state_machine.py
@@ -1,7 +1,8 @@
 """
 This module contains specifications of SKA state machines.
 """
-from transitions import Machine, State
+from transitions import State
+from transitions.extensions import LockedMachine as Machine
 
 
 __all__ = ["OperationStateMachine", "AdminModeStateMachine", "ObservationStateMachine"]