More young SA mums 'abused by partners'

Girls as young as 13 are being physically and sexually abused by their partners, an Adelaide support shelter for young, at-risk, mothers says.

More than 80 per cent of girls coming to Centacare's Louise Place shelter say they've experienced domestic and sexual abuse, manager Vicki Lachlan says.

Increased access to pornography and peer pressure among young men has sparked a dramatic increase in abuse in recent years, she says.

"Young girls are being asked to perform things that, particularly, the younger boys have seen," Ms Lachlan told AAP.

"The peer groups talk about violence and they enact violence and see if they can better the violence."

Ms Lachlan said about 85 per cent of the girls who have come to Louise Place this year have experienced domestic violence and sexual assault, compared to fewer than half of young mothers in the previous decade.

"A 15-year-old young woman came to us pregnant and her 14-year-old partner was already controlling everything she did ... what phone calls she made to whom, her contact with her family and what she did in her day-to-day activities," Ms Lachlan said.

Schools needed to introduce mandatory relationship education as early as primary school.

"There needs to be more emphasis on normal, safe, healthy and respectful relationships," she said.

"It has to happen early. It has to happen in primary school, not just high school.

"By then, it's often too late."