Prime Minister Najib Razak has thrown his weight behind the contentious bill, which seeks to incorporate parts of the Islamic penal code, or "hudud", into Malaysia's existing Islamic legal system.

Najib, who is currently embroiled in a corruption scandal, is hoping to burnish his Islamic credentials in order to boost his chances in national elections that must be held by August 2018.

Critics of the bill warn that it could pave the way for full implementation of hudud, which prescribes punishments such as amputations and stoning, and disrupt the fabric of Malaysia's multi-cultural and multi-religious society.

"The so-called 'empowerment' of the Shariah Court will only exacerbate the unequal treatment of Muslims and non-Muslims before the law," said Bebas, an NGO that organised a smaller counter-rally.

No official figures were available on how many people attended Saturday's peaceful support rally in Kuala Lumpur, but estimates were in the tens of thousands.

Tuan Ibrahim Tuan Man, deputy president of the hardline Islamist opposition Parti Islam-se Malaysia (PAS), one of its organisers, said 100,000 people were expected to attend.

The PAS presented the bill in parliament last year but later withdrew it in order to fine tune the legislation. It is now expected to be reintroduced in the next parliamentary session, in March.

Najib, who has resisted calls to resign over a scandal at state fund 1Malaysia Development Berhad (1MDB), where he was an adviser, backed the bill despite the anger of members of his own United Malay National Organisation (UMNO) ruling coalition.

Lawsuits filed by the U.S. Justice Department in July last year said nearly $700 million of the misappropriated funds from 1MDB flowed into the accounts of "Malaysian Official 1", who U.S. and Malaysian officials have identified as Najib.

Najib has denied any wrongdoing.

Presidents of three parties representing the Chinese and Indian ethnic groups in Najib's ruling Barisan Nasional (BN) coalition have threatened to quit their cabinet posts if the bill passes.

For decades, PAS has been pushing for Malaysia to adopt hudud in the northeastern state of Kelantan that is governed by the party, arguing that it is the responsibility of the country's Malay-Muslim majority to support Islamic law.

Criminal cases are currently handled by federal law in Malaysia, where Malay Muslims account for more than 60 percent of the 30 million population.

The Shariah courts come under the jurisdiction of each state and are limited to family law covering issues such as divorce and inheritance.

Supporters of the legal reform said Saturday's rally also aimed to allay the fears of minority groups.

Ismail Borhan, 33, an engineer who attended the rally, said the objective of the bill was to allow commensurate action that can act as a deterrent to wrongdoing.

"Those opposed to the bill have a lack of understanding and exposure (to Islam), simply opposing for the sake of opposing," he said.

REUTERS