Tony Abbott has moved to pour cold water on talk of a bulk billing co-payment fee as the Griffith byelection enters its final week, but Labor has labelled the Prime Minister's comments ''weasel words''.

The Griffith campaign has been dominated by the controversial proposal - put to the federal government's Commission of Audit - to end free doctor visits and charge patients $6 per visit.

Liberal National Party candidate Bill Glasson, a former Australian Medical Association president, came out in favour of the proposal last month but has since backed away from his comments.

Speaking after Dr Glasson's campaign launch on Saturday, Mr Abbott sought to draw a line through the issue before next week's poll.

''Nothing is being considered. Nothing is being proposed. Nothing is planned,'' he said.

However, when pressed, Mr Abbott did not guarantee there would be no co-payment.

Labor candidate for Griffith Terri Butler seized on the Prime Minister's comments.

''We all know those are weasel words,'' she said. ''Why does he think the people of Griffith are going to fall for those weasel words? If they were going to categorically rule it out, they should have done so today.

''But instead there's this 'no plans' language, when we all know because [Treasurer] Joe Hockey admitted as much, that this is still on the table and it's still being considered in the Commission of Audit.''

Campaigning in a Greenslopes park, Ms Butler and opposition health spokeswoman Catherine King cut a large Medicare birthday cake to celebrate 30 years of the health scheme.

At his campaign launch, Dr Glasson defended his record on Medicare.

''Health is my passion … when I was the AMA president we worked extremely hard to ensure we got more money into Medicare,'' he said.

Cameron Atfield