Senate Democrats say they will press for a vote as early as Tuesday to address a $1 billion shortfall in the budget for veterans' health care programs.

Two congressional panels have summoned Veterans Affairs Secretary Jim Nicholson (search) to Capitol Hill to testify about the VA's miscalculation of how much would be needed for the current fiscal year for veterans' health care. VA officials told the House Veterans Affairs panel that additional costs for veterans returning from Iraq and Afghanistan and poor budget forecasting contributed to the problem.

Even before further details are known, Democratic senators fashioned amendments for a pending Interior Department spending bill, ranging from a $600 million proposal by John Kerry (search), D-Mass., to a $1.4 billion plan by Robert C. Byrd (search), D-W.Va.

Nicholson is expected to testify that the VA can juggle its budget — taking $600 million in capital infrastructure spending and $400 million in carry-over funding for next year — and avoid the need for emergency funds for the current budget year ending Sept. 30.

Funding for next year is another question, and lawmakers are likely to face pressure to add emergency funds for veterans' health care programs above the $28.8 billion approved by the House last month.

The current shortfall may give Democrats a potentially potent political issue. They sought to give the VA an extra $2 billion this spring while Congress assembled an $82 billion emergency spending bill on war and homeland security, but the VA said it didn't need any more money.

"The administration told Congress that additional funds were not needed to care for our veterans. We now know that this claim was wrong," Byrd said.

Republicans caution that more information is needed before they endorse any effort to address the problem.

"We need to know what the budget numbers are," said Senate Veterans Affairs Committee GOP spokesman Jeff Schrade. "The bottom line is, veterans are going to be taken care of."