The Australian Medical Association says the Abbott Government has enacted “a very sly way of cutting the [health] budget.”

Patients will be hit with a new $20 fee for seeing their GP as part of changes to Medicare snuck in by the Federal Government to save billions of dollars.

The changes begin to take effect from next week, and are estimated to cut $500 million from Medicare in 2015.

There has not been much of a stir about the “10 minute” rule, which is predicted to blow out GP waiting times from January 19 after the latest adjustments to see Medicare paying $20.10 less for consultations lasting six to 10 minutes.

It means that people who currently pay to see their GP will receive $20.10 less back from Medicare for consultations up to 10 minutes, so that their “out of pocket” cost or “gap fee” (the difference between a doctor’s charges and the amount a patient receives back from Medicare) will increase.

Previously, Medicare paid $37.05 towards such “Level B” visits, which were made by millions of patients each year when they sought a new prescription or simple blood pressure check, for example.

But now Medicare will pay just $16.95, leading doctors to warn free universal healthcare will suffer greatly.

“This change alone will kill off a lot of bulk-billing,” Dr Michael Levick, a spokesperson for the AMA's Victorian branch told Fairfax Media this week.

“This is a very sly way of cutting the [health] budget.”

Chair of the AMA's council of general practice Brian Morton says Medicare payments were already failing to keep up with the costs of running a practice, and when the new changes take effect many GPs will simply stop bulk-billing and charge a fee for short consultations.

“[Or] it may be that patients and doctors extend the consultation unnecessarily to get over that 10-minute threshold and that will impact on access,” Dr Morton said.

“If you can do an efficient, good-quality consultation for eight minutes that is relevant to the patient's circumstances and needs, it doesn't take long before those two minutes add up to block another patient coming in.”

Last financial year about 26 per cent of 134 million visits billed to Medicare were under 10 minutes.

The new fees will be compounded by separate moves to impose a $5 cut to all Medicare rebates for GP consultations for non-concessional patients from July 1.

This means people without a concession who see a GP for less than 10 minutes will receive a rebate of just $11.95.

Doctors are planning rallies to protest in all major Australian cities on February 8 to raise their voices about the changes, as well as moves to freeze indexation of the Medicare rebate until 2018.

A spokesperson for Health Minister Sussan Ley claims the changes to consultations under 10 minutes will encourage longer GP consultations for better health outcomes.

“Under the current rules, a GP can access Medicare rebates for up to 20 minutes, even if their patient is in and out the door in six minutes,” the spokesperson said.