The Medicare levy is paid by everyone (most people, in some circumstances you can get an exemption)
It is not related to PHI

The Medicare levy surcharge is and additional 1.5% again which you pay if your combined income exceeds a certain amount and you don't have PHI. For 2010-2011 this was $154,000

If your income after tax deductions was 154,000 and you had no health insurance your Medicare surcharge would be $2310

If your combined income was less than that, you wouldn't have to pay the surcharge