Airport security earn a bit more 14k per month. Not sure if you need to speak fluent Cantonese. Bear in mind security jobs in general requires you to work 6x12 hours per week and has day/night shifts.
If you have a military background try to find a job as bodyguard for VIPS. One of our building's security (Sun Hung Kai) served as a military in Indonesia. Somehow he got attention from the old Mrs Kwok and she hired him as a personal bodyguard. Pay 40k. I have to add he is good looking.