Deb Frecklington says her elevation to Opposition Leader spells trouble for Premier Annastacia Palaszczuk, warning her it is "game on" in the next term of government.
Ms Frecklington, who was deputy leader under Tim Nicholls, defeated former leader John-Paul Langbroek in a party room vote on Tuesday afternoon to become the first woman to lead the merged LNP.
The Nanango MP said she and her new deputy Tim Mander represented an opportunity for the party to "reset" after losing several seats at the state election.
"Queenslanders have spoken in the last two elections, and the job ahead of us is to get out there and rebuild the faith of those Queenslanders," Ms Frecklington told reporters.
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"As the new leadership team in Queensland we have pressed the reset button, but we are under no illusions of the hard work that we will have to do."
Ms Frecklington acknowledged the party had made "some mistakes" during the election campaign, but sidestepped questions about what exactly they were.
Her selection is the first time in Queensland's history both the premier and opposition leader are women.
Ms Palaszczuk in her victory speech last week noted the milestone, but said it didn't matter who the LNP selected as leader because she'd faced down several LNP leaders and come out on top.
Ms Frecklington said Ms Palaszczuk would now have to "run on her own record" instead of raising the spectre of former premier Campbell Newman to criticise the LNP.
"We've got two years and 10 months to take on this Labor party and I can say one thing to Annastacia Palaszczuk - it is game on because we will be a formidable force at the next election," Ms Frecklington said.
The new LNP leader does represent a return to the past in one way for Queensland's conservative party - her seat of Nanango centred on Kingaroy is largely the same electorate held by long-serving Queensland premier Joh Bjelke-Petersen.
The vote breakdown from the LNP party room is meant to be kept under wraps, but Ms Frecklington entered the meeting on Tuesday flanked by dozens of members - including her predecessor Mr Nicholls - while Mr Langbroek was only joined by party stalwart Mark McArdle.
Several MPs who spoke to AAP on Monday said Ms Frecklington's recruitment of potential rival Mr Mander to run as her deputy had given her the upper hand in a potentially tight vote.
Mr Mander's decision to give his support to Ms Frecklington had surprised many with some in the party warning the move could undermine his chances of claiming the leadership in the future.
On Tuesday he was in lockstep behind his new leader.
"The party's vote for Deb and myself means they've voted for renewal," Mr Mander said.
