"They ruled her conversion to Islam wasn't valid... Her declaration of faith was there but she didn't fulfill all the other conditions," he told The Associated Press. "She didn't practice."

Ahmad Munawir said the court "has made it clear that Muslims can't simply renounce the religion as long as their conversion is done in a proper way and he or she is accepted as a Muslim."

But Tan, whose first name before she converted was Ean Huang, said she never practiced Islam and converted in 1998 only to marry an Iranian Muslim. In 2006, she filed a request to renounce Islam after her husband left her.

Christians, Buddhists and Hindus have increasingly complained in recent years that they face discrimination, including unfavorable court decisions in conversion cases and temple destruction.

Tan's case follows another victory for religious minorities earlier this month when an Islamic court ruled in favor of a Christian man who was given an Islamic name at birth. The National Registration Department had refused to allow the man to drop his Islamic name when he applied for a new identity card.

But in many other instances in past years, courts have ruled in favor of Muslims, including refusing to let those who are Muslim-born leave Islam and accepting claims that people converted to Islam before their deaths despite family objections.

Malaysia has a dual court system for civil matters — Shariah courts for Muslims and secular courts for non-Muslims, which make up more than a third of the country's 27 million people. In interfaith disputes, the jurisdiction of the courts has often clashed, and Shariah courts usually have the last word.