A coalition of Muslim NGOs has threatened to campaign against Muslim MPs who don't support PAS president Abdul Hadi Awang's controversial bill to amend the law on punishments imposed by syariah courts.

Ummat secretariat chairperson Aminuddin Yahaya said the motion - which seeks to push for amendments to the Syariah Court (Criminal Jurisdiction) Act (Act 355) - will only affect Muslims, and as such there was no reason for Muslim MPs to oppose it.

"We are issuing an ultimatum. They (Muslim MPs) have to support (the motion).

"If Muslim MPs oppose (the motion), we will, in the 14th general election, campaign in their parliamentary constituencies and explain that these are the leaders who opposed the strengthening of Islamic laws," Aminuddin said when met outside Parliament today.

He was there as part of a demonstration to show support for Hadi's motion.

Some 70 people, many clad in black and white jubahs, were lined up along the bridge leading to Parliament, holding placards to voice their support for Hadi’s motion.

The motion was to tabled for debate in the House about 12.15pm today.

The motion is on a bill seeking to raise the present punishment cap under syariah law to 30 years’ jail, RM100,000 fine and 100 strokes of the whip.

The current syariah punishment cap is three years’ imprisonment, RM5,000 fine and six strokes of the whip.

Aminuddin stressed that these amendments would only affect Muslims, and that lawmakers from parties such as DAP should explain this to their constituents.