The political turmoil in Malaysia has entered a new and potentially more confrontational phase with the formation of two broad based coalitions to push for sweeping reform and the removal of the prime minister, Mahathir Mohamad.

'Reformasi' has become a rallying cry

It is a highly unusual development in a country where opposition parties have traditionally been divided along racial lines and where all anti-government activity has been routinely suppressed.

The slogans shouted by crowds who have thronged the streets of Kuala Lumpur tell their own remarkable story: "Reform!" and "Mahathir Resign!".

Such open defiance of the authorities was unthinkable a few weeks ago. But there is a growing boldness among the opposition movement.

The two new formations have pledged to work together, and there is a large degree of overlap between their aims and membership.

Leaders of the Coalition for People's Democracy vowed to fight injustice and what they called the rape of democracy.

The second formation, calling itself the People's Justice Movement, has as one of its priorities the abolition of the draconian Internal Security Act, which was originally introduced by the British authorities in the colonial period.

Different races fighting under same banner

The coalitions bring together people from disparate backgrounds, from Islamic fundamentalists to women's rights advocates, from veteran socialists to environmentalists.

Anwar says he was beaten up by police

Perhaps most significantly, parties representing different ethnic and racial constituencies are now fighting under the same banner.

The challenge they face is to provide coherence and direction to a movement which draws on vastly different political cultures. Fissures may yet appear.

But the increasingly reviled figure of Dr Mahathir himself gives a focus to the protests, as does the outrage felt at the rough treatment of Mr Anwar and his supporters.

It is not yet clear how Mr Anwar's wife, Wan Azizah Wan Ismail, will align herself with the new groupings. She has become a forceful advocate for reform since her husband's arrest.

Mahathir exposed as never before

However, some opposition leaders have distanced themselves from his "Reformasi" movement, seeing it as too closely bound up with his personal fortunes and the future of the ruling UMNO party.

The opposition faces other dilemmas, too. By taking the calls for reform off the streets and into the formal political arena, they hope to appeal to the many Malaysians, and particularly the disgruntled middle classes, who fear mass political unrest.

Anwar's arrest has sparked a chain of protests

Yet the tight restrictions on the media and on all forms of peaceful political association leave few other avenues open to them if they really want to exert pressure on Dr Mahathir.

Dr Mahathir has a battery of repressive legislation at his disposal to deal with the opposition.

Yet the traditional methods of snuffing out dissent are no longer working. Calls for reform are increasing, and are being voiced from within the majority Muslim Malay community, which controls the police, army and bureaucracy.

By concentrating power in his own hands, Dr Mahathir has left himself exposed as never before. The coming weeks could see the most serious challenge yet to South East Asia's longest serving leader.