The US state of Missouri is trying to raise its minimum age for marriage from 15 to 17, in a bid to address growing concerns over sex trafficking and forced unions.

The Midwestern state is one of 27 where parents are able to sign off on their children’s marriages from the age of 15.

But even younger children can lobby the courts for permission if they want to get wed.

Now government officials have given preliminary approval to a proposed new law that would raise the age of parental consent to those over the age of 17.

It came as child protection groups warned the state was becoming a haven for forced child marriages, attracting “marriage tourism” from other parts of the country.

Citing a case from last year when a father brought his pregnant 14-year-old from Idaho to marry a 24-year-old man in Kansas City, Missouri state representative Jean Evans sponsored the proposal to raise the age.

Jan Jones, the former head of the Recorders Association of Missouri, was also forced to issue a marriage licence to a pregnant 15-year-old girl and her husband in his mid-20s, after the girl’s mother signed her consent.

She told the St Louis Post-Dispatch she was “haunted” by the situation after child protective services informed her the pregnancy was being investigated and that the marriage meant the state Children’s Division was powerless to continue looking into the girl’s situation.

Advocacy groups have condemned the cases, highlighting that when minors marry older adults they engage in relationships that would otherwise amount to statutory rape.

At age 18, emancipated adults are free to marry on their own in Missouri and all other states.

The measure, which still needs final approval in the House before moving to the Senate, is not the first initiative to change the practice.

In Connecticut, new legislation would prohibit marriage licenses for anyone under 18.