Malaysia has used a powerful national security law to arrest a man and woman over suspicion of spreading rumours of riots in the capital over the Internet last week, police said on Wednesday.

The Malaysian Bar Council, the country's body for lawyers, said while it supported the arrests, it disagreed with the use of the Internal Security Act (ISA) which provides for detention without trial.

The suspects should have been detained under the Telecommunications Act, which covers false transmission of news on the Internet, said Mr Cyrus Das, president of the bar council.

". . .It will be appropriate and in accordance with the law if alleged offenders are dealt with under the specific provisions dealing with the subject of rumour-mongering where the safeguards of a trial are present rather than to be detained without trial under the ISA," Mr Das said in a statement.

Malaysia's police chief, Inspector-General Abdul Rahim Noor, was quoted by the national Bernama news agency on Tuesday as saying that a man and woman, in their early 20s, had been detained under the ISA to help police in their investigations of the rumours that shook Kuala Lumpur last week.

The rumours, that Indonesian labourers and locals clashed in a downtown area of Kuala Lumpur on Friday, sent panic through the nation.

They caused a sharp weakening of Malaysia's ringgit currency in overseas trading and forced the police and government to issue a denial through the media.

Mr Abdul Rahim said police could detain the two suspects for up to 60 days initially.