Yasamin Alttahir, 17, was placed on detention after she refused to stop wearing an ankle-length manto to Auburn Girls' High School in Sydney.
The school eventually agreed to let her continue wearing the religious garment after she obtained a permission note from her parents.
Bob Carr, premier of New South Wales state, has supported Alttahir's right to dress according to her faith.
"Let's tolerate the difference in our community," he told reporters. "Young women, conservatively presented, not dressed like Britney Spears, turning up to school."
Carr called for an end to media debate about Alttahir, an Iraqi-born Shia Muslim, who has been accused of being a troublemaker by some talkback radio presenters for defying school uniform policies.
"I just think we've got to be careful that we don't traumatise a young woman who's at school to get her education and training and set herself up for life," he said. "I think we should give the issue a rest."