KABUL, Afghanistan - Afghanistan's counternarcotics minister has resigned and is reported to be taking up a diplomatic posting in Canada.

Word of the resignation comes from the deputy counternarcotics minister, who says Habibullah Qaderi submitted his resignation to President Hamid Karzai about five days ago.

Gen. Khodaidad says the resignation was voluntary and was driven in part by health problems, although he says Qaderi has taken a new position as Afghanistan's consul general in Toronto.

However, the Afghan Embassy in Ottawa says no such decision has been made.

"The introduction and appointment of a new consul general in charge of the Afghan Consulate in Toronto is pursued through established diplomatic channels,'' the embassy said in a statement Sunday.

"Any final decision in this regard will officially be made public in due time.''

Qaderi's resignation comes just weeks after Afghan labourers finished cultivating an opium poppy crop that is expected to equal or exceed last year's record haul.

Qaderi headed the ministry since December 2004 and survived several cabinet shuffles. But Afghanistan's poppy crop has ballooned under his watch and the country's production last year accounted for more than 90 per cent of the world's heroin supply.

Western and United Nations officials have said this year's harvest would equal or exceed last year's record crop.

The resignation comes as behind-the-scenes negotiations take place in the Afghan government and western embassies -- notably the United States' and Britain's -- about how to tackle the growing drug problem.

The U.S. has said it wants to spray the crop with herbicide like it does with coca plants in Colombia, a controversial idea that was rejected by Karzai for the 2007 growing season. Britain, whose troops are in charge of Helmand province, the world's largest poppy growing region, has said it would support a limited spraying program.

Gen. Dan McNeill, the top general in charge of NATO-led troops in Afghanistan, has said he expects western soldiers to step up efforts to combat the drug trade, though they would not be involved in manual eradication of poppy fields.

A significant portion of the profits from the country's $3.1-billion US trade is thought to flow to Taliban fighters, who tax and protect poppy farmers and drug runners.

Khodaidad said Qaderi did a "wonderful job'' in Afghanistan's north, where cultivation is expected to drop, but said "we have some problems'' in the south, where violence has spiked this year. The poppy crop in Helmand province in particular is expected to soar this year and will likely account for more than 50 per cent of the country's poppies.