Longman signals federal Labor win: Shorten

But Prime Minister Malcolm Turnbull has downplayed the impact of Susan Lamb's win in the marginal seat of Longman, after a blow to his government in Saturday's cross-country by-elections.

During a victory lap in Narangba, north of Brisbane, Mr Shorten said voters had made a clear choice.

"Wherever I travelled in Australia, including Queensland, I found a growing appetite amongst everyday Australians to see more fairness and more equality in Australian society," he told reporters on Sunday.

"If Mr Turnbull just thinks that that's all a fairytale ... that everything's fine, that he's just going to keep offering us more of the same, well then I think he'll pay an electoral price for that."

The message from Ms Lamb and her Labor colleagues to Queenslanders was clear: Us versus them.

Labor made the by-elections a choice between standing up for the little guy or siding with the big end of town.

The Liberal National Party's campaign was rattled by revelations that candidate and former Campbell Newman minister Trevor Ruthenberg lied about being awarded a defence force medal.

Primary support for the party has now dropped from around 44.8 per cent in 2013 to a figure closer to 28 per cent.

But Mr Turnbull said the results were unremarkable, if not expected.

"This was a conventional swing in one electorate, absolutely an average swing," he told reporters in Sydney.

"So there is not a lot to celebrate for the Labor party. There is certainly nothing to crow about."

The working class Longman electorate, named after Queensland Parliament's first female MP Irene Longman, has been seen as a potential indicator of the federal result.

It borders Peter Dutton's seat of Dickson, one of five LNP seats where the margin is below two per cent.

Labor's win in Longman has given the party confidence it can pick up other marginal seats in the key battleground state.

"The real test of a public opinion and political opinion is obviously at elections," Mr Turnbull said.

"By-elections do have special characteristics, for all the reasons we understand and we've discussed."

Australian Associated Press