Canada said Thursday it is pulling out of a UN convention that fights drought, mostly in Africa, becoming the only nation to walk away from a pact that Ottawa says is a waste of money.

Prime Minister Stephen Harper's Tory government quietly ordered the withdrawal from the 1994 convention last week, ahead of a scientific meeting on the agreement next month in Germany.

On Thursday, Harper lamented to the House of Commons that only "18 percent of the funds that we send to this particular organization are actually spent on programming."

"The rest goes to various bureaucratic measures. That is not an effective way to spend taxpayer money," he declared.

The move provoked an outcry from non-governmental aid agencies, environmentalists and the opposition, which accused Ottawa of isolating Canada and abandoning Africa through "maniacal" budget cuts.

"What's shocking about Canada withdrawing from this UN convention is that there are 194 signatories to this convention. That's everyone in the UN," said opposition New Democratic Party MP Paul Dewar.

"Now there are 193 signatories to this convention because Canada is the only country on the entire planet that is not part of this convention."

The Canadian International Development Agency will honor its Can$315,000 (US$310,000) commitment to the United Nations Convention to Combat Desertification secretariat for 2013. But it will be its last payment.