Malaysia's opposition on Thursday slammed the lifting of an export ban on long-tailed macaques, saying the monkeys faced being slaughtered for food or suffering horribly in experiments.

The government said last month it had lifted a 23-year ban on the export of the inquisitive monkeys because they have become a menace in urban areas, creating havoc by attacking people and stealing food.

"These poor wildlife primates will be destined for the cooking pot and be subjected to horrendous suffering in ... laboratories," Democratic Action Party vice-chairman M. Kula Segaran said in a statement.

He also said that exports could breach wildlife protection legislation as the monkeys are listed in the Convention on International Trade in Endangered Species (Cites).

Environment Minister Azmi Khalid said last month that there were more than 258,000 macaques living in urban areas in peninsular Malaysia and nearly 484,000 in the wild.

Newspapers have reported that the government is in negotiations to export the primates to Hong Kong, South Korea, Taiwan and Japan.

Segaran said that Azmi should make clear who would profit financially from the export of macaques, and say whether it had considered more humane methods like sterilisation or human culling.

As many as 10,000 macaques were exported each year in the 1970s, mainly for laboratory research in the United States and Europe and to other countries as exotic food or pets.

The trade led to a drop in the macaque population and subsequently forced the government to impose the ban in the mid-1980s.