Coalition frontbenchers concede the Turnbull government will need to rethink its approach and listen to minor party voters after failing to win a Super Saturday by-election.
Cabinet minister Christopher Pyne says the government has to talk to One Nation voters in Queensland to "make sure we're listening to what they have to say".
Another frontbencher Dan Tehan said the party will need to rethink its approach to election campaigns, after Labor won four by-elections on Saturday.
"In any loss, you've got to be prepared to learn from it," he told Sky News on Sunday.
Prime Minister Malcolm Turnbull is now under pressure to change tack on some of his key policies and rethink his approach to One Nation.
With vote counting continuing on Sunday, Labor's Justine Keay, Susan Lamb and Josh Wilson - who resigned from parliament over their dual citizenship - were set to return to Canberra to represent Braddon, Longman and Fremantle.
Labor's primary vote went backwards in Braddon but Ms Keay kept the seat.
"A win is a win is a win," Labor deputy leader Tanya Plibersek told the ABC.
Former Kevin Rudd staffer Patrick Gorman will become the MP for Perth, and the Centre Alliance's Rebekha Sharkie regained the South Australian seat of Mayo.
Bill Shorten helped Susan Lamb celebrate her win in the Longman by-election. Source: AAP
Labor framed the by-elections as a choice between "hospitals and the big banks", taking aim at the government's plan to cut taxes for Australia's biggest businesses.
Mr Pyne said the coalition aimed to get its company tax cuts through in the spring sittings of parliament, although he admitted it would be tough.
"Selling company tax cuts for small and medium enterprises is a lot easier than selling them for larger companies," Mr Pyne told the ABC.
Uncertainty over school funding and cuts to penalty rates were also factors at the ballot box.
Incoming Labor president Wayne Swan described the results as a "complete rejection and utter humiliation" for the prime minister.
"We've had an emphatic, absolutely emphatic big tick for Bill Shorten, his handling of the policy issues and his approach over the last five years," Mr Swan told the ABC.
Mr Shorten described the result as "another signpost into the destination that matters for Australians - a Labor government after the next general election".
Labor candidate for Braddon Justine Keay celebrates her with supporters. Source: AAP
Mr Turnbull is unlikely to call an election until close to when it is due in May 2019.
The Liberal Party declined to concede in Braddon, but candidate Brett Whiteley was not confident of getting the preferences needed to win.
Ms Lamb's win in the Queensland seat of Longman, with an expected 54.5 per cent of the two-party preferred vote, came on the back of a One Nation drain of LNP votes.
A similar swing at a general election could topple senior government figures such as Home Affairs Minister Peter Dutton.
