Yes u can work in SIngapore with an EP pass...
Just like the CHina nationals who claim to be "PEIDU Study mamas" but at night, they go donk donk and be massage parlors and other seedy vice trades part-time.....
that is why most of them are deported back.....huge crackdown i tell u...
But as an EP holder, u can work.....but as part-timer, so that the gov can't track your money flow thru CPF contributions....
Try it, ! you'll be better off rather than searching for a perm job