(AFP) - Malaysia's Internal Security Act (ISA), a relic of the battle against communist guerrillas half a century ago, was once described by a critic as the "Indefensible Suppression Apparatus".

Rights groups and opposition politicians have campaigned vociferously for the repeal of the 1960 Act, which superseded pre-independence legislation, and of other laws which allow detention without trial.

Prime Minister Mahathir Mohamad and his predecessors have used the act repeatedly to detain opposition supporters and others deemed to be a security threat, as well as suspected criminals.

Late yesterday and today at least seven opposition supporters were detained under the ISA in advance of planned weekend protest meetings in support of Mahathir's jailed former deputy Anwar Ibrahim.

Police can detain and interrogate suspects for 60 days. After this the home affairs minister must sign an order authorising the detention and stating reasons for it.

The order is issued for a two-year period but can be renewed indefinitely.

"Security authorities sometimes wait several days after detention before informing an ISA detainee's family," said the US State Department's human rights report issued February.

The total number currently held under the ISA is not known. The State Department cited a local human rights group as saying that as of Nov 30, there had been 76 detentions under the ISA during last year.

Operation Lallang

Veteran opposition leader Lim Kit Siang, now chairman of the Democratic Action Party, was detained under ISA for 17 months in 1969 and for 18 months in 1987, when Mahathir launched "Ops Lalang" (Operation Lallang).

About 107 people, including opposition supporters, were detained under Lalang. A period of racial tension was cited as justification.

ISA was also used in 1990 during a period of strained relations between Kuala Lumpur and the-then Sabah state government. Later in the 1990s members of the Darul Arqam religious movement were held.

On Sept 20, 1998, police broke down Anwar's front door and detained him for three weeks under ISA before filing criminal charges. Some 27 supporters were also held.

Lim said this week's use of the ISA was "completely unwarranted," saying opposition supporters were planning a peaceful gathering this Saturday to mark the second anniversary of Anwar's sentencing to six years for abuse of power.

He said that authorities "seem to be looking for an excuse for a crackdown ... there is a sense that he (Mahathir) is losing control and unable to regain support."

Lim speculated that Mahathir's deputy Abdullah Ahmad Badawi, who is also home minister in charge of police, had opposed the use of the act.

Physical abuse

He said for the first 60 days detainees could be denied lawyers.

"For the first two or three weeks they (police) see if they can break you," he said. "There was no physical abuse in my case but sometimes there have been serious cases of torture.

"You are helpless, of course."

Lim said Malaysia's first prime minister Tunku Abdul Rahman justified the 1960 act to deal with the aftermath of the 1948-60 communist "Emergency".

"Now there is no need for it. If they have proved offences have been committed or are likely to be committed, they should act under the laws of the land rather than the infamous ISA."

He said the use of open-ended allegations gave authorities "carte blanche to detain anyone they like. They don't have to prove anything".

Lim said detainees were held in solitary for the first 60 days, then in a detention centre. "You never know when you will be released."