The requests Monday, to accompany President Bush's budget for the fiscal year beginning Oct. 1, would bring the total appropriations for 2007 to about $170 billion, with a slight decline the following year.
The additional request for the current year includes $93.4 billion for the Pentagon — on top of $70 billion approved by Congress in September — and is about $6 billion less than the Pentagon's request to the White House budget office.
Bowing to pressure from Congress, the administration will also break down the $145 billion request for next year into detailed form.
For 2009, the White House assumes spending will be down to $50 billion, with no funding planned beyond then in hopes the war in Iraq will have wound down.
Mr. Bush has said his five-year plan will bring a balanced budget by 2012, but the claim has met with some skepticism from Democrats since the White House has declined to forecast long-term war costs.
"If we're successful carrying out the president's current policy, we would hope that we'd begin to have less of a financial commitment even in this fiscal year," said the senior administration official, who spoke on condition of anonymity because the budget won't be unveiled until Monday. "This is our best guess."
The spiraling increases in war spending — up from $120 billion approved by Congress for 2006 — are largely to replace equipment destroyed in combat or worn out in harsh conditions in Iraq and Afghanistan.
The Iraq requests are certain to face scrutiny by the Democratic-controlled Congress, which is debating whether to try to block Mr. Bush's request to increase troop levels in Iraq to quell the burgeoning violence in Baghdad.
War critics also say the Pentagon is using war funding requests to modernize the armed services with weaponry — such as the next-generation Joint Strike Fighters or the controversial V-22 tilt-rotor aircraft — unlikely to see action in Iraq or Afghanistan.
The Administration defends such acquisitions since the Joint Strike Fighter would replace F-16s lost in Iraq, and there are no assembly lines open for the 30-year-old airplanes.
The additional budget request for Iraq is far below ambitious lists assembled by the service branches, who were given a green light last fall by Deputy Defense Secretary Gordon England, who instructed the four military services that they could add projects connected to the broader fight against terrorism. Critics said that could be interpreted to cover almost anything.
Those lists were met with resistance in the White House and on Capitol Hill, and the Pentagon pared them back in the request it forwarded to the White House's Office of Management and Budget, which trimmed them further.
The war costs come on top of a record request for the Defense Department's core budget, which is expected to reach about $480 billion in 2008.