A 16-year-old Sydney girl has taken her parents to court over an arranged marriage and won.

She has won the right to be placed on an airport watch list so her parents can't take her from the country for an arranged marriage in Lebanon.

The girl approached the Legal Aid Commission in secret, which the court said was becoming increasingly common.

According to Federal magistrate Joe Harman, although it might seem that the young woman, given the pseudonym Ms Madley by the court, bucked her parents' authority, she showed great bravery in seeking legal assistance.

"The young person's evidence makes very clear that she has expressed to her parents that she does not want to go to Lebanon and does not want to marry the person proposed," he said.

"She has indicated also in her evidence that she is fearful for her personal safety, that she has concerns as to what will occur in relation to her mother's reaction once she becomes aware of these proceedings.

"It is not the right of any parent to cause their child to be married against their will, whether in accordance with Australian law or otherwise."

He said there was a psychological risk to Ms Madley if she was forced into a marriage she didn't want, which he said was "a principle that is contrary to all our legal processes hold dear and which would indeed, under Australian law, render the marriage void, as it is absent genuine consent."

He ordered that Ms Madley not be removed from Australia by her parents and told them they must not assault, molest, harass, threaten or intimidate her, or question her about the court proceedings.

He also ordered that her passport be surrendered to the court and for her to be placed on the airport watch list so the Australian Federal Police keep an airport watch for her.

The wedding was supposed to take place two weeks after the court's judgment.

If the wedding were to take place in Australia, the girl's age means a court order and parental consent would be required.

Despite the judgment, Mr Harman said he wasn't criticising any culture that had arranged marriages.

"The arrangements proposed should not be judged or criticised from a Western perspective, but must be viewed through the eyes of those who live and appreciate that culture," he said.