The coalition should match Labor's promise to pour an extra $2.8 billion into public hospitals if it wants to avoid another "Mediscare" campaign, doctors warn.
Ahead of Saturday's five by-elections, the Australian Medical Association's boss says voters are watching health spending closely.
Labor sent out text messages at the 2016 election that looked like they came from Medicare, falsely claiming the coalition planned to sell it.
That campaign - dubbed 'Mediscare' - is no longer allowed under law changes introduced this year.
"I note that Labor has pledged an extra $2.8 billion for public hospitals," AMA president Tony Bartone told the National Press Club on Wednesday.
"I expect that the coalition will match that as the election draws nearer. They do not want another 'Mediscare' style campaign."
Dr Bartone said after the by-elections another general election would be held within 12 months.
"There is nothing like a federal election to help our political leaders share the public's interest in good health policy," he said.
"There must be a plan to lift public hospitals out of their current funding crisis, which is putting doctors and patients at risk."
Labor has been campaigning hard on health in the electorates of Longman and Braddon, where the party is in danger of losing to the coalition.
Opposition Leader Bill Shorten said in Longman on Wednesday the by-election was "all about health care".
"Labor stands firmly and squarely on the side of putting hospitals before banks, putting patients before multi-millionaires," he said.
But latest polling puts both seats on a knife edge going into Saturday.
In one poll, Liberal candidate Brett Whiteley was slightly ahead of Labor's Justine Keay but in another, the former Labor MP who resigned over her dual citizenship had the edge.
Preferences from One Nation's candidate Matthew Stephen will be crucial to determine whether the Liberal National Party's Trevor Ruthenberg can defeat Labor's Susan Lamb in Longman.
But Labor deputy leader Tanya Plibersek played down talk voters might be upset with Ms Lamb for causing the by-election.
"No. I get a sense that they're a bit tired of the by-election, I'd give you that much," she told reporters.
The South Australian seat of Mayo is expected to be reclaimed by the Centre Alliance's Rebekha Sharkie, while the other by-election seats of Perth and Fremantle are expected to remain in Labor hands.
