Academic Gowns and Hood Colours for Overseas Students Where the University Does Not Have One
Ask the university. There will be administrative offices and a secretariat of some kind, and they will be delighted to be able to help. It is a lot more interesting than most of the stuff they find themselves having to do.

The general rule is to wear the gown and hood corresponding to this university's equivalent degree if there is one, so if you are a masters student then presumably you will have a bachelor's degree and so the B.A. dress would be appropriate. But ask them, and they will happily tell you.