A youth advocacy group has pledged to refer the LNP to the United Nations over a plan to house 17-year-olds with adult offenders in Queensland.

On Wednesday, the LNP announced it would build two medium-security, 90-bed facilities to house 17 to 25-year-olds, at a cost of $40 million.

The LNP plans to build two reintegration centres, which would be medium-security facilities for 17 to 25-year-olds offenders.

Labor's bail houses would be scrapped, and the 17-year-olds would be dealt with under the Youth Justice Act, despite being placed with offenders aged 18 to 25.

In September 2016, legislation passed to allow 17-year-olds to be moved into the youth justice system and out of adult jails.