A Malaysian Hindu woman fighting to keep her children after her husband and son converted to Islam launched a last-ditch bid in the nation's highest court Monday.

In one of a series of cases that have highlighted racial tensions in multi-ethnic Malaysia, R. Subashini's battle began when her husband converted in May 2006, along with their eldest son, four-year-old Dharvin Joshua.

The husband then launched proceedings in an Islamic sharia court for divorce and custody of their second son, two-year-old Sharvin.

Subashini, 28, has been battling to stop her divorce from being decided in the religious court but has twice failed to obtain an injunction. She now faces her final chance in the Federal Court.

"The husband should be restrained from using the judicial system in order to get orders from the sharia court which will adversely affect the rights of the wife even though she cannot appear in that court," her lawyers said in a submission.

Subashini's lawyer, Malik Imtiaz Sarwar, told reporters that she has not seen her eldest son for more than a year since his conversion, which she is contesting in a separate legal action.

"We've lost the case twice but in the court of appeals there was a minority judgement... which we are relying on," he said of the Federal Court bid to halt the divorce.

Malaysia's civil courts operate parallel to sharia courts for Muslims in areas of personal law, including divorce and child custody. Non-Muslims say they fear they will not get an equal hearing if referred to a sharia court.

Subashini's case is one of a series of legal battles between Muslims and non-Muslims, who say their rights are being undermined in the mainly Muslim nation.

Malaysia's population is dominated by Malay Muslims, who live alongside large ethnic Chinese and Hindu communities.

The hearing in the Federal Court was set to continue on Tuesday.