Physios are not allowed private practice unless you are approved by SMC-Singapore Medical Council, and this can be between 2 to 4 years.

And foreign grads may have to undergo a period of supervised service.

Take a look at the SMC website, and the MOH website, as per the link from Ms Swan.

Private hospitals would be willing to pay a higher salary, if your credentials add value to their business.

Anyway, do google for salary scales of Physios, and take a look at the SGH/NUH/TTSH websites.

Good luck