Speculation over Prime Minster Tony Abbott’s leadership is set to mount with yet another poll showing voters continuing to abandon the Coalition, and a disastrous election result in Queensland.

Counting in the Queensland election showed Labor on track to possibly snatch a majority victory and as many as 46 seats, in a remarkable comeback after having won just seven seats in 2012.

Queensland Premier Campbell Newman lost his seat of Ashgrove and has quit politics. In a speech announcing the decision, he urged his party to meet as soon as possible to elect a new leader.

• Ashgrove voters sack Campbell Newman
• Massive swing to Labor in QLD poll 

The result came as a Galaxy Poll to be published in News Corp’s Sunday newspapers showed the Abbott government behind the Opposition 57 to 43 per cent on a two-party preferred basis, compared to 55 to 45 per cent in December.

The prime minister’s personal approval rating is wallowing at 27 per cent.

Attorney-General George Brandis moved to downplay suggestions Mr Abbott’s future as Liberal leader was even more in doubt following the poll, and the election result.

“He had a terrible week. Nobody doubts that. I would have expected that the next poll would look bad and it does,” Senator Brandis, who was on Sky News as part of the channel’s Queensland election analysis, said on Saturday night.

But he maintained Mr Abbott would remain Liberal leader and would lead the Coalition at the next federal election.

“You asked me a question: do I believe that Tony Abbott will lead us to the next election? Yes I do and I think he should because he is the best person to be the prime minister in this country.”

There have already been accusations from within Queensland Liberal-National ranks that Mr Abbott and federal issues had severely damaged the LNP’s and Mr Newman’s prospects.

At about 8pm, two hours after polls closed, the ABC’s Antony Green said it was possible Labor could form a majority government .

“We have 79 of the 89 seats we are giving away to one side or the other and the Labor Party is closer to majority than the LNP. I’m predicting Labor to win 46 seats, which would be majority government,” he said.