Mirex in high doses is known to cause cancer and is banned in Canada and severely restricted in the United States. DDVP is a potential carcinogen and restricted in Britain and India, and the US prohibits its use around infants and elderly and sick people.

The Agriculture and Fisheries Department controls pesticide imports and agriculture officer Ian Hunter said the mirex and DDVP available in the territory were in formulations and concentrations considered safe.

But Friends of the Earth, in a report on pesticides in Hong Kong, said the effect of long-term exposure to these and other chemicals was not known and there should be tighter controls on them.

Some recent evidence overseas has suggested long-term exposure to some pesticides may be linked to breast cancer and other health problems. Only 10 per cent of known pesticides have been assessed for health effects.

Friends of the Earth said the department had made good progress in controlling the import of many chemicals over the past five years, but more controls were needed on their usage.

''It's very difficult to legislate for pesticide use but only the least harmful should be registered for use. If there are potential long-term health or environmental effects, they should be withdrawn,'' campaigns co-ordinator Lisa Hopkinson said.

Ms Hopkinson and volunteer Jenny Monks compiled the report and said information about pesticide use and impact was sketchy, but they found a study in 1985-88 showed Hong Kong women had a high level of pesticide DDT in their breast milk, which may be linked to cancer.

Levels of DDT in cow's milk also rose tenfold between 1984-87 and 1992-93, according to government laboratory tests they cited.

There is no research on how pesticides are used in Hong Kong and, although imports for non-agricultural use are declining, they still totalled 1,341 million tonnes last year, most of it moth repellants and aerosol insect sprays.

''Misusing these can leave people prone to incidents of poisoning,'' Ms Hopkinson said and she noted pesticides were a major cause of children's poisoning elsewhere. There are no statistics for Hong Kong.

The report also looked at pesticide contamination in food from China, which has caused more than 100 people to be poisoned in Hong Kong in each of the past three years. People were advised to buy only those vegetables accredited under a forthcoming scheme of the Agriculture and Fisheries Department which will indicate the farms using only safe pesticides.

Ms Hopkinson said water supplies were also at risk. Although they were not believed to be affected at present, two proposed golf courses, at Kau Sai Chau and Shalotung, are in water catchment areas and any pesticide run-off could be a problem.

Pesticides also affected wildlife and the Shalotung course proposed using diazinon which kills birds, she said.

Ms Hopkinson and Ms Monks said pesticides had their benefits because they reduced crop losses and spoilage, but worldwide they were overused and in the US the only benefit of 60 to 80 per cent of pesticides used was to make vegetables and fruit look more attractive.

In addition to calling for tougher controls on pesticides allowed for use in Hong Kong, they proposed increasing the penalties for offenders from the current $2,000 and six months in jail.