An attempt to bring to a House vote a plan to allow federal employees to phase into retirement has suffered a setback but there is still a chance the proposal will come to a vote, potentially as soon as today, Capitol Hill officials said.

Under a proposed amendment to the pending defense spending bill, a federal employee could retire when eligible but at management’s discretion could continue working for the government part-time, receiving a prorated annuity and a prorated salary.

The amendment was not among those approved Wednesday evening by the House Rules Committee for a separate floor vote, but it still might be considered under a procedure in which numerous proposals are bundled for a collective vote, Capitol Hill officials said Thursday morning. However, chances of that happening were uncertain.

The plan, initially proposed by the Obama administration, passed the Senate in March as an amendment to a bill involving transportation policy that has since stalled. In April the House Oversight and Government Reform Committee approved the plan as a freestanding bill, with bipartisan support.

Under the proposal, offered by Rep. Stephen F. Lynch (D-Mass.), phased retirees typically would work half-time, collecting half of the annuity they have accumulated to that point plus half of the salary for the position. However, with agency approval they could work between 20 percent and 80 percent of the time, with both the annuity and the salary prorated accordingly.

Currently, with some exceptions, federal retirees who return to work for the government receive their full annuity but have their salaries reduced by that amount. Supporters of the phased retirement plan say the offset is a disincentive to those who wish to continue doing some work after retirement, and deprives agencies of their expertise.

Phased retirees generally would spend part of their time mentoring younger workers, under the proposal.

Another part of the proposal would allow employees who separate from the government for retirement or other reasons to invest in the Thrift Savings Plan the value of unused annual leave due to them.

That language also was part of the bill passed last month by the oversight committee, and further was included in a spending-cutting bill that passed the House last week, but that the Senate does not plan to consider.