Malaysia's two newly-appointed Sharia women judges will not be allowed to rule on criminal or divorce cases, according to a top official, who denied the religious courts were biased.

The government announced the appointments earlier this month as proof of its commitment to transforming the Islamic legal system, which runs parallel to civil courts in the Muslim-majority country.

Sharia appeal court judge Mohamad Yusup Che Teh said that a committee of 20 senior Islamic judges in a month's time would determine the exact role of the two women elevated to the Sharia bench.

"The two female judges will only hear civil cases, they will not hear criminal cases. They cannot hear divorce cases but they will be able to hear cases related to custody (of children), alimony and common property," he said.

"We will decide what cases they can hear based on the religion. It is not discrimination but following the rules of the religion," he told a news conference.

"Islam can accept changes to serve the needs of society, but it has to be within the principles of Sharia."

Suraya Ramli, 31, was appointed a Sharia judge in the administrative capital of Putrajaya while Rafidah Abdul Razak, 39, was made a Kuala Lumpur Sharia court judge.

"It's a heavy responsibility which Allah has given me. I will carry out my duties responsibly," Suraya told the news conference.

Activists say that women face discrimination in Islamic divorce proceedings, inheritance and child custody cases, with courts slow to penalise husbands who fail to pay alimony.

However, Mohamad Yusup disagreed.

"The perception that Sharia courts are biased is not true, there is no gender bias, we hope we can get more women judges in other states nationwide," he told the news conference.

He said there was a need for more female judges in the Islamic court system across the country as it heard an average of 70,000 cases a year. The majority are related to divorce, custody and alimony cases.