Schools across the country could face a wave of legal complaints if uniform policies do not modernise to allow girls to wear shorts and pants, South Australia's Equal Opportunity Commissioner has warned.

Key points: SA's Equal Opportunity Commissioner has written to private schools over uniform policy

SA's Equal Opportunity Commissioner has written to private schools over uniform policy Dr Niki Vincent wants all schools to allow girls to wear shorts and pants

Dr Niki Vincent wants all schools to allow girls to wear shorts and pants She said some were opening themselves up to potential discrimination complaints

Niki Vincent said attitudes towards uniforms were "stuck in another age" and has written to principals at independent and faith-based schools across SA urging change.

She said a failure to offer gender-inclusive uniform policies could breach equal opportunity and anti-discrimination laws.

"The whole country is behind in terms of having inclusive uniform options," Dr Vincent said.

"There's gender-stereotyping issues about what girls should wear and what boys should wear that concern us.

"When girls are allowed to wear trousers or shorts, we know that they do a lot more physical activity.

"If wearing pants and wearing shorts means that they can run around and have as much freedom to do whatever they want to do in the schoolyard — hang upside down on the monkey bars, sit cross-legged on the floor — I think that should be the case."

Last year, the WA Government made it mandatory for schools to offer girls the choice of wearing pants or a dress to school, but other states have refused to follow suit.

In South Australia, uniform policies are highly variable, especially throughout the private sector, and Catholic Education SA has asked schools to review them "in light of the needs" of current students.

So far there have been no complaints about the issue to the commissioner's office, but Dr Vincent said it was only a matter of time before that changed.

Dr Vincent said research showed uniform choice influenced sporting participation. ( Hailey Renault )

She said there had been several recent legal battles in New South Wales involving parents who had challenged school policies.

"We see this as an area that many schools don't often understand clearly," she said.

"We want to work with them to both clarify the issues and to establish a more inclusive uniform policy as a matter of urgency."

Uniform policies in hands of individual schools

Currently, SA Education Department guidelines require dress codes to be flexible "regardless of a student's gender" to allow for "freedom of movement, level of comfort [and] safety", among other factors.

But the policy only applies to government schools, and "independent and faith-based schools set their own policy", a department spokesperson said.

According to Dr Vincent, most government schools "understand their obligations in this regard".

"This isn't the case with many private schools in the state and we want to help them in establishing more inclusive uniform policies," she said.

Dr Vincent said a lack of uniform choice could reinforce stereotyping. ( ABC News: Elise Pianegonda )

The state's Independent Schools Association said that uniform policy was in the hands of individual schools — a position echoed by Catholic Education SA (CESA).

"Each of our schools makes its own decisions about school uniform," CESA director Dr Neil McGoran said.

"Many of our Catholic schools already offer pants or skirts as an option — particularly in primary settings.

"Some schools offer a choice of dress or long pants in winter and shorts or dress in summer.

"All of our schools are encouraged to offer uniform options that meet the needs of their students. We encourage schools to review their uniforms in light of the needs of their current students."

Dr McGoran added that schools were "aware that when school uniform policy is being updated that issues of gender inclusivity should be considered".

The commissioner said uniform choice was also important for students who were "struggling with their gender identity".

But she added independent and religious schools were handling those issues "in a sensitive way".

"There are a lot more students who are feeling comfortable to come out about gender identity," Dr Vincent said.

Flinders University psychology expert Dr Sarah Cohen-Woods, who also represents the group Girls Uniform Agenda, supported the push for change on the grounds of both equal opportunity and health.

"Wearing dresses and skirts at school often raises modesty issues that boys simply don't face," she said.

"It can be the difference between girls doing cartwheels on the grass, playing on the bars or joining a football game, or just sitting down all lunchtime."