Government costing co-payment plan that would exempt vulnerable patients

The Abbott government is crunching the numbers on potential changes to its unpopular GP co-payment that would exempt pensioners and other vulnerable patients.

Health Minister Peter Dutton says the coalition is "seriously" considering the proposal from the Australian Medical Association as it attempts to get the $7 co-payment through the Senate.

The doctors group opposes the original model for the impost, which charges all patients $7 to visit the GP.

Key Senate crossbenchers David Leyonhjelm and Bob Day have also called for a rethink on the co-payment, while it has been rejected outright by the Palmer United Party.

Mr Dutton said the government was costing the AMA's co-payment model as part of negotiations with the doctors group.

"We're seriously having a look at what they're suggesting but some of the other crossbench senators have had suggestions to make as well," Mr Dutton told Fairfax Radio.

"We'll work with them and have a look at suggestions that they've made."

Labor leader Bill Shorten said the government should scrap the co-payment altogether.

"The whole GP tax is a clunker, it's rotten, it's unfair," he told reporters in Sydney.

Former Liberal treasurer Peter Costello has also urged the government to cut its losses and dump the $7 co-payment - a suggestion that was today dismissed by Mr Dutton.