Hardening his stand against anti-government protestors including the ethnic Indians, Malaysian Prime Minister Abdullah Ahmed Badawi on Monday said he would "sacrifice" public freedom in order to maintain national security in the country rocked by a spate of agitations.

Badawi said he would not "sacrifice his sense of accountability to the greater public, especially in the face of police intelligence about planned fighting or other violent intents."

"If the choice is between public safety and public freedom, I do not hesitate to say here that public safety will always win," Badawi said while delivering the Khazanah Global Lecture Series in Kuala Lumpur.

His comments came a day after police detained 21 opposition members and lawyers for staging "illegal" rallies.

Last week 31 ethnic Indians were arrested on charges of attempted murder of a policeman when they assembled for a rally against their alleged marginalisation, which was banned by the government.

"Malaysians must never, ever, take their peace for granted and they must continue to be responsible to each other," he said.

"If we are to evolve into a society that can peacefully live with media freedom, public debates or public show of expression, the value and the burden of responsibility must lie with the ordinary people, not just with those who manage the country," he said.

"In this age of relative affluence and stability, we sometimes forget that there are many groups within the country -- each with their own set of demands, each with their own set of sensitivities," he noted.

"These differences are very real, yet we do not descend into sheer unmitigated chaos," Bernama newsagency quoted him as saying.

He said political fairness could be seen in the practice of power-sharing where all the major races were represented in government via a seat-sharing formula set up by the ruling coalition.

Malaysian police on Sunday arrested 21 people, including 12 opposition leaders as it continued its crackdown on anti-government protestors who defied a ban to take out a rally in Kuala Lumpur.

About 50 people, including lawyers and activists, wearing surgical masks, staged 'Peace Walk' past Kuala Lumpur's landmark Independence Square, to mark World Human Rights Day but were stopped by over 300 policemen.

Meanwhile, four lawyers and four activists pleaded not guilty at a sessions court on Monday to two charges of being in an unlawful assembly and defying police orders.

They were alleged to have participated in Sunday's 'Walk' in Jalan Tuanku Abdul Rahman.

Multicultural Malaysia has a 60 per cent population of Malays while the rest is made up of 7.8 per cent ethnic Indians, 25 per cent Chinese and others.