The Food and Environmental Hygiene Department has published an online home page saying modified foods on the market are safe, but the Government is studying the feasibility of mandatory labelling.

Greenpeace campaigner Lo Sze-ping, who has been fighting for labelling laws, warned officials not to use the campaign to give the public a false impression of safety.

'They are bound to fail if they try. But if they just want to raise awareness, then the campaign should be welcomed,' he said.

Labelling laws are unlikely to be passed before 2003 because a special United Nations commission will not finish setting international safety and testing standards before that date.

The department's deputy director, Dr Leung Pak-yin, has said such laws may violate World Trade Organisation rules on free trade. However, a new UN protocol on biosafety was finalised in Montreal in January and will come into effect when ratified by 50-member countries. It could override the organisation's rules in areas of biotechnology.