MPs have asked ministers to provide more details of spending in Iraq and Afghanistan - expected to increase to nearly £2bn this year.
Defence committee chair James Arbuthnot said ministers should not take MPs' support for spending plans for granted.
MPs questioned why Iraq costs were forecast to rise by 2% next year, when the number of troops were falling.
The Ministry of Defence said this was because of building and infrastructure work at the base at Basra Airport.
Forecast costs of operations in Iraq and Afghanistan in 2007-8 are due to rise by 2% and 39%, respectively.
Troops reduced
In its report, the defence committee said it was not surprising that Afghanistan costs were rising to £964m, given the intensity of fighting in the southern province of Helmand.
But it questioned why overall spending Iraq was due to rise by 2% on 2006/7 rates to £955m, despite the withdrawal of almost all troops to Basra airbase.
"The government should not take Parliament's agreement to its spending plans for granted"
Defence Secretary Des Browne has asked Parliament for additional funds of £1.91bn, to cover the bill for Iraq and Afghanistan.
The committee recommended MPs approve the request, but Tory MP Mr Arbuthnot added: "Few people will object to the investment made this year in better facilities and equipment for our troops in Iraq and Afghanistan.
"The money spent on better-protected fighting vehicles is particularly welcome. But a lot of public money is being spent on these operations, and the MoD needs to provide better information about what it is all being spent on.
"The government should not take Parliament's agreement to its spending plans for granted."
The MoD said Iraq spending was due to rise because of building and infrastructure work on the airbase, where most troops are based, as well as improved protection of Warrior armoured vehicles and replacement of Land Rovers with Protected Patrol Vehicles.
But the committee asked why personnel costs for Iraq were only expected to fall by 5% - despite troop numbers being reduced from 5,500 in May 2007, to 2,500 from spring 2008.
The committee also predicted the bill for 2007-8 operations would rise further in the next round of estimates in the spring.
^ Back to top | BBC Sport Home | BBC Homepage | Contact us | Help | ©
~RS~q~RS~~RS~z~RS~09~RS~)