The cost of Canada's war in Afghanistan in the current budget year is forecast to hit $848.6 million, says a document tabled in Parliament on Monday.

The bill for the military mission now is expected to be $331.1 million higher than forecast in the budget presented last winter by Finance Minister Jim Flaherty.

The extra funding will be used to cover the "additional cost of operations" in Kandahar, including equipment support, ammunition, repair and overhaul of the army's battered combat vehicles, immediate care for wounded soldiers and support to their families, as well as engineering support on the ground.

The Defence Department has been under pressure over the last year to keep the cost of the mission in line, and was warned by the Conservative government against asking for additional appropriations.

Monday's supplementary estimates, which must get House of Commons approval, also ask for an additional $90.4 million to pay for a two per cent pay increase for members of the Forces, which was announced in June but backdated to April 1, 2008.

During the election campaign, Parliament's budgetary officer estimated the overall cost of the Afghan mission could reach $18.3 billion by the time Canadian troops withdraw from the fighting in 2011.

But Kevin Page conceded his figure was only a best guess because it contained difficult variables, such as the future care of wounded soldiers.

Defence lobbyists have raised concerns in the last few weeks that falling government revenues, combined with the continuing cost of the war, might mean that long-planned equipment purchases will be sidelined.