Another part of the trick is that the government will now cut some rebates by much more. Standard so-called Level B consultations of up to 10 minutes currently attract a $37.05 rebate. Under the changes they will classified as Level A and attract $16.95 for the young and concession holders and $11.95 for everyone else.

And the two-year freeze on increasing the amount of Medicare rebates that was going to extend to June 2016 will now become a four-year freeze, extending to June 2018.

Doctors will lose just as much as before, but in different ways and for longer.

At least that's what the budget update will say.

All of the changes but one will be introduced through the back door by regulation rather than by legislation, which requires the approval of Parliament. But regulations can be disallowed by the Parliament after they are introduced. Just last month the Senate disallowed the regulations that purported to water down consumer protection under financial advice law.