Manufacturers and distributors of about 350 food products ranging from baby food to rice have refused to pledge that their products will remain free of genetically modified ingredients, according to a newly released shopper's guide on GM products.
The guide, published by Greenpeace for the fifth consecutive year, detailed the pledges made concerning 589 products in 17 food categories.
Pledges were made in relation to about 40 per cent of the products. In the chips and biscuits category, however, guarantees were given for only 20 per cent of such products, in responses to a survey in August and December last year.
The food categories surveyed - mostly offered by local supermarket chains - also included oil, drinks, ice cream and confectionery.
Apple Chow Yuen-ping, a Greenpeace campaigner, said there had been some new guarantees given by manufacturers and distributors in relation to new products.
But some chewing gum brands, such as Extra and Airwaves, had refused to renew guarantees that their products would remain GM-free.
She said the world's biggest food supplier, Nestle, and canned soup manufacturer Campbell had not made pledges.
Ms Chow urged the government to require GM labelling on food products, because a voluntary scheme launched since 2006 had failed.
A Greenpeace study in February found none of 800 selected food items were labelled to indicate the presence of GM ingredients.
'We hope this is the last time we publish the guide,' she said. 'Only with the expedient implementation of mandatory labelling can consumers in Hong Kong be genuinely protected.'
A Food and Health Bureau spokesman said there was still no international consensus on mandatory GM food labelling, a process that was seen as likely to increase business costs.
He said an assessment of the voluntary scheme was under way.