The Liberal National Party has pledged to trial a youth curfew in Townsville to stem crime as it campaigns for the Queensland election.

LNP leader Deb Frecklington says crime is out of control in the garrison city, where her party is aiming to pick up three marginal Labor seats on October 31.

Under her plan, youths under the age of 14 will have to be indoors by 8pm while youths aged 15 to 17 will need to be off the streets in the city by 10pm.

Those caught by police without a reasonable excuse will be taken to local community refuges to be supervised, potentially overnight.

Parents will be fined $250 on every occasion one of their children is caught outside during curfew.

“The youths are laughing in the face of the police officers, they are laughing in the face of the government because Labor is soft on crime,” Ms Frecklington told reporters on Wednesday.

“If you do the crime, you should do the time.”

The LNP leader said a similar curfew worked in Western Australia and her plan would also put youths in front of the social services they needed.

Tweet from @DebFrecklington

Campaigning south of Townsville, Premier Annastacia Palaszczuk promised to build a freight highway between Charters Towers and Mungindi.

“A second Bruce Highway would take trucks off the existing Bruce, making it safer for communities from Gympie to Townsville,” she wrote on her Facebook page on Wednesday morning.

“An inland freight route will also reduce travel times, support jobs and increase economic activity.”

Tweet from @AnnastaciaMP

Her promise rivals an earlier pledge by the LNP to widen the existing Bruce Highway from two to four lanes for 1450km from Curra to Cairns.

Ms Frecklington’s plan would cost $33 billion over 15 years, with the state chipping in $440 million annually and the federal government expected to cover the rest.

The LNP leader is flying to Cairns later on Wednesday to pledge $180 million to upgrade Cairns Hospital into a university hospital.

“The university hospital will catapult Cairns health services into a new era, and patients will be able to get advanced treatments at this state-of-the-art facility,” she said.

“Far north Queensland has waited too long for its fair share under Labor.”

Ms Palaszczuk has also promised funding of $67.9 million to upgrade to Cairns Hospital.

She has pledged to work with James Cook University to revamp the facility so students can practise medicine there.

Queensland’s northern regional cities are being targeted by both major parties, with One Nation and Katter’s Australian Party also campaigning heavily.

Ms Palaszczuk received a boost on Tuesday night, with an Essential Poll showing she enjoys a 62 per cent approval rating.

She is the third most popular premier after Western Australia’s Mark McGowan and NSW’s Gladys Berejiklian, according to the survey.

The Electoral Commission of Queensland said on Tuesday 228,000 ballots had been cast in pre-poll voting across the state.

More than 820,000 people have applied to vote by post.

-AAP