Amnesty International Australia campaigner Joel Mackay, meanwhile, says a pre-emptive curfew would only "entrench cycles of disadvantage, poverty, poor health and racism".
"Youth prisons will once again overflow. It will affect the most marginalised children in our communities who need support and only get more children trapped in the quicksand of our justice system," Mr Mackay said in a statement.
"The reality is that curfews do not work – the UN Guidelines for the Prevention of Juvenile Delinquency note that curfews ‘stigmatise, victimise and criminalise young people'."
He also said the policy, described by Amnesty as "extremely concerning", may breach Australia's commitment to international law if enacted. Both the Committee on the Rights of the Child and the UN World Report on Violence Against Children have called for the abolition of status offences such as curfews, Mr Mackay said.
Under the LNP election pledge, police would be able to detain youths found on the streets of Townsville and Cairns, which have large Indigenous populations, after curfew.
People under the age of 14 would have to be indoors by 8pm, while those aged 15 to 17 would need to be off the streets by 10pm.
The teens would be forced to stay in a community refuge until they're picked up by family. Parents would also be fined $250 every time one of their children is detained.
"We would need to amend the legislation to give the police the power ... to take the children from the streets and put them in the refuge," Ms Frecklington said.
"This is all about keeping our children and our community safe. I will not apologise for being tough on crime."
LNP candidate Glenn Doyle said detained children could be connected with social services.
"They do come from dysfunctional families, but we need to have the opportunity to engage them with health, with child services, with youth justice," he said.
However, Queensland Greens MP Michael Berkman said the LNP was "blowing its racist dogwhistle" and perpetuating "the blatant lie" of a youth crime wave.
Change the Record, an Aboriginal-led justice coalition, said in a tweet that Aboriginal and Torres Strait Islander children would be most affected by punitive curfews, in circumstances where they were already 23 times more likely to be incarcerated in Queensland than non-Indigenous children.
Indigenous federal Labor MP Linda Burney, meanwhile, said she did not support the curfew and wanted more information from the LNP on how it would apply.
“The issue of youth crime has some very deep reasons and the important thing is not a quick fix and a politically expedient fix at that,” she told Sky News.
Labor led the LNP 51 per cent to 49 per cent on a two-party preferred basis in a Roy Morgan poll released on Wednesday.
The pollster said Labor's primary vote was up 0.6 per cent to 36 per cent since 2017, while the LNP's has risen 1.3 per cent to 35 per cent.
Meanwhile, Labor's border closure to NSW was backed by 51 per cent of respondents.
Roy Morgan said 51 per cent of men wanted the border to reopen, while only 43 per cent of women wanted the change.
Queenslanders go to the polls on 31 October.
Additional reporting by AAP.