However in Thai the Tax Id is not mandatory, even most Thai people do not have one.
In fact I request every year a tax residence ro22 certificate from Thai tax office that report my passport number instead of tax id and state that I am resident here.
I also go every year at foreign affair office (dfa), in order to stamp it, then translate and stamp again at embassy of my origin country.
I do this every year.
International Bank compliance are aware of the fact that tax id in some country are not mandatory and usually there is a checkbox on the form the Bank provide that says something like "tax id is not required on my country of residence" or something like that.
Sometimes they do not have this checkbox . That's happened to me sometimes.
In that case I sent an Email with scan of tax residence from tax office (ro22), and stamp of foreign affair office (dfa) and my embassy, explaining on the email the fact that here tax ID is not mandatory and if they don't believe me they can check on internet or even with their legal department.
After that, never had problems, I always passed every Banking application.