The Queensland police union has sparked controversy by requesting tougher laws that could see pregnant women forced into institutions if they drink alcohol or take drugs.

The union wants the power to lock up "risk-taking" mums-to-be to protect their unborn babies.

Union president Ian Leavers has argued for the law change in a submission to the Queensland child protection inquiry.

He cites fetal alcohol syndrome and children born with drug addiction as reasons the state should be allowed to intervene, and says the state's focus should be on the rights of the unborn baby, not the "rights and liberties" of the mother.

"The cost to society in providing care and assistance to children born with ailments solely as a consequence of the actions of the mother during pregnancy is astronomical," Leavers said in the submission.

"Those children also deserve a right to full life and health and should not be disadvantaged simply because of the actions or inaction of their birth mother.

"The state must have the ability to intervene and protect the unborn child when its mother refuses, or is incapable or unwilling, to do so."

Queensland has a growing problem with pregnant women who take drugs. The child protection enquiry has heard that one baby is placed on a drug-dependence program every week in the Gold Coast region.

Social work expert Rosamunde Thorpe, who has worked in Queensland communities for years, has blasted the union's request, branding it "draconian".

"I think it's very perturbing, very, very perturbing," she told The Australian newspaper.

"There would need to be far more safeguards built in."

Queensland's child protection inquiry is being headed up by former Family Court judge Tim Carmody. He is expected to release his final report in April.

Your say: Do you think police should have the power to lock up pregnant women who might be putting their unborn babies at risk?