Generally, entry-level consultants here are paid around 4-5k SGD... However, as you're a ph.D holder, you may be able to rise up faster. Thus, the annual increment could be very high, possibly 20%, depending on your performance.

As an alternative, being a Prof. in Singapore certainly pays very well. Starting with Asst. Prof, you will be able to earn around 5K plus oportunities for paid overseas trip(s) for conference(s). In addition, if you're not a Singaporean, NUS/NTU will top-up the salary for you accordingly (as this $$ is supposed to be credited to any local professionals at up to 14.5% of stated monthly salary, thus u'll earn up to 114.5% of contracted salary, excluding bonuses. YES! Teachers/Professors in Singapore do earn bonuses!)

Cheers!