Malaysia’s top court said in a landmark decision on Monday that both parents must consent to the religious conversion of a minor, ruling unanimously in favour of a Hindu woman whose ex-husband converted their three children to Islam without telling her.

The ruling ended a nine-year legal tussle for M Indira Gandhi, whose former husband became a Muslim and converted their three children in 2009. He also snatched their daughter, then 11 months old, from the family home.

She won custody of the three children and challenged their conversions in civil courts of Malaysia’s dual-court system. A lower court annulled them, but the Court of Appeal overturned the ruling, saying civil courts had no jurisdiction over Islamic conversions. The ruling was appealed to the nation’s highest court.

The five-member panel in the Federal Court found the children’s conversions unlawful as they were done without Gandhi’s consent.

“This is a landmark decision and a victory for all Malaysians,” said M Kulasegaran, Gandhi’s lawyer.

He said the ruling clearly showed civil courts are the paramount courts and can hear matters related to Islamic affairs even if there is a contradictory Sharia court decision. There are many similar disputes involving the unilateral conversion of children to Islam and that the ruling meant that non-Muslims now can seek redress in the civil courts, he added.

Muslims, who are 60 per cent of Malaysia’s 31 million people, are governed by Islamic courts while non-Muslims go to civil courts to settle family, marriage and other personal disputes. But the law is vague on which court has authority over disputes between Muslims and non-Muslims, especially within a family.

Civil courts have generally avoided taking a position in such cases, allowing Sharia courts to lead. This has raised questions about freedom of religion guaranteed by the Constitution, and strained racial relations in this multiethnic country, which has enjoyed largely peaceful race relations for nearly five decades.

Critics accuse the ethnic Malay Muslim-dominated government of doing too little to resolve problems. The government has become increasingly reliant on support from Islamist and right-wing pressure groups as other constituencies flock to the opposition.

Last year, the government withdrew a proposed law that sought to end unilateral conversions of children ahead of general elections due in the next few months.

An emotional Gandhi told local media that she was thankful for the decision and that there is “no more excuse” for police not to find her former husband, who has refused to comply with court rulings to hand her youngest daughter back to her. He has gone missing and police earlier said they couldn’t act on the civil court’s order.

“But my daughter is still missing. I want to see her. I really need to hold her. It has been nine years. When is she going to come back?” she said.