It is a "word" or just an exclamation that Sabahans commonly use to say "Shoo!".
Specifically to a dog.
That's all there is.
Oh, and another variant:
-Sika po!
A: Sika! Anjing, budu.
(With the variant)(Basically the same thing)
A: Sika po! Anjing, budu.
Sika(sivakarthikeyan) is a dummy bundai who cries in all state shows
Sika