Weeks after the Veterans Affairs Department acknowledged a major shortfall in its health care budget, members of the House and Senate agreed Tuesday to provide $1.5 billion to close the gap.

Negotiators for the two chambers settled on the amount already approved by the Senate -- which comes on top of $28 billion already approved for the budget year ending Sept. 30 -- after key House lawmakers said they had lost faith in the VA's estimates. A final vote is expected this week.

The House originally passed a separate $975 million bill to close the veterans health care shortfall. That step was based on administration estimates. Only days later, the administration boosted those cost estimates by $300 million. That was the latest of a string of ever-increasing VA estimates of the size of the problem.

Veterans Affairs Committee Chairman Steve Buyer (search), R-Ind., said that in April the administration said it could fix the VA health care problem by reshuffling $600 million of department funds.

Later, when the problem was inflated to a $975 million shortfall, majority Republicans said they would appropriate new funding rather than accept administration guarantees that it could manage the problem by rearranging funds in its maintenance accounts and using a budgetary cushion.

Now, with the latest estimate, Congress is tuning out the department.

"We go from $600 million to $975 million to $1.275 billion. What's it going to be in August?" Buyer asked. "There is a loss of confidence here in the House with regard to the number that has been given to us."

The emergency funding comes on top of $28 billion approved last year as part of the VA's regular budget.

The additional money is necessary to correct underestimations by the Veterans Affairs Department of the number of veterans seeking care and well as increased costs of treatment and long-term care. But the manner in which the VA has estimated how much would be needed for veterans health care has proven faulty.

For starters, the VA's estimating models for the original budget submission did not take into account the additional cost of caring for veterans injured in Iraq and Afghanistan. Demand for health care services has increased by more than 5 percent over last year. The VA originally predicted growth of about 2 percent.

The $1.5 billion for the fiscal year ending Sept. 30 is in addition to $2 billion in increased demands for the upcoming year relative to Bush's February budget request.

Democrats said that even with the additional funding, the veterans health care system is under great strain.

"We have heard many, many horror stories," said Rep. David R. Obey, D-Wis. "We have heard that thousands of patients have had to wait more than three months for appointments in California. We have heard that in (several) states ... the VA has stopped scheduling appointments for many veterans who are eligible for care."