A few years ago I helped a woman from Newcastle who was in a somewhat similar situation. She arrived on a tourist visa, her boss told her she didn't need to worry about a work visa. First month came, her boss paid her 15% of her regular salary. Did the same for three months consecutively, kept saying they'd give her the rest next month. I spent a month persuading her that she was being screwed. Finally, she called me one night and said, 'please help me get out of here and get home.' I sprang for her ticket home, she promised to repay me but I knew she couldn't, so I wrote it off to good karma.
Anyway, that's an aside. How long have you been working there? I'm not sure if you are being screwed because I don't know what your personal relationship with them is, but from the sounds of it, you are in a position where they could very easily screw you over.
with all of your documents in their hands, they can keep you from working legally elsewhere. So even if you were to look for another job and want to get a proper work visa, your current 'boss' has all the necessary documents. Fortunately you still have your passport so you can leave the country anytime you want. BUT:
the longer you are here on a tourist visa, the more likely it is Customs and Immigration will question you when you eventually do leave. They will want to know what you've been doing all this time. And if they suspect you've been working illegally, they might decide to refuse you a work visa in the future should you leave the country and come back.
you have NOTHING to make your employer pay you. No legal contract, no work visa, not even a bank account. So what's to stop him from saying, 'fuck off' when you finish working there and not pay you a dime? Not a thing.