(AFP) The government will keep a draconian security law which allows detention without trial but will use it judiciously, Deputy Prime Minister Abdullah Ahmad Badawi said today.

The feared Internal Security Act (ISA), a successor to a British colonial law passed to battle a communist insurgency, is not an anachronism, said Abdullah, who is also home (interior) minister.

"We will retain the ISA," he told a press conference after opening the annual meetings of the youth and women wings of the United Malays National Organisation (Umno).

"It is important for us under our circumstances ... in the implementation of any provisions of the ISA, let me assure you that we will be responsible."

Abdullah last month authorised the detention without trial of six supporters of jailed ex-deputy premier Anwar Ibrahim, sparking widespread outrage and mounting calls for the ISA to be repealed.

The government says they planned violent street protests to topple Prime Minister Mahathir Mohamad's administration. No evidence has been made public.

Opponents say the ISA is being abused to stifle peaceful political dissent.

Asked how the government justifies continued use of the ISA, Abdullah said: "It is our business ... our duty and our mission to ensure that we are not in any way threatened by anything that can cause problems to the country.

"Because we have preventive laws, because we have taken action, that's why you see things are okay."

'Subversive threats'

Abdullah said the nation must be vigilant against "subversive threats" which were becoming serious but gave no details.

"I am not an alarmist ... (but) it is important that we are always aware ... the precondition to the success of our development efforts is that Malaysia must be peaceful and there is political stability and security," he added.

Earlier in his speech, Abdullah warned the government would not tolerate "radical changes through violent revolution that can lead to the loss of lives".

"Democracy does not mean allowing rabble-rousing which can lead to violence and instability ... violent street demonstrations are something that cannot be condoned," he said.

"We must not allow ourselves to be manipulated by external forces pursuing their own agenda."

Abdullah also pledged support to the premier, saying there was "no dispute" to the leadership of Mahathir who marks his 20th year in power next month.