(Adds Democratic Leader Pelosi, other details)
WASHINGTON, Dec 20 (Reuters) - Republicans in the U.S. House of Representatives, lacking the votes to pass legislation to keep the federal government functioning beyond midnight Friday when existing funds expire, floated new proposals late on Wednesday in the hope of averting agency shutdowns.
Leading House Republicans were canvassing rank-and-file members on the floor of the chamber into the evening before deciding how to go forward, with Friday's deadline fast approaching.
A closed-door meeting led by House Speaker Paul Ryan brought a revolt among some Republicans who want guarantees of more military spending, according to lawmakers in that meeting.
Ryan ideally would like to put a temporary spending bill to a vote on the House floor on Thursday, giving the Senate time to process the legislation before the midnight Friday deadline.
But it still was not clear whether he would get the necessary 217 votes from House Republicans that would be needed if all Democrats vote against the bill, as they have been threatening.
House Democratic Leader Nancy Pelosi has urged her rank-and-file to vote 'no' unless Democratic priorities are addressed, such as quick passage of a "Dreamer" immigration bill to protect undocumented immigrants who entered the United States years ago as children.
Republican leaders say they want to address that issue next year.
According to one person who observed the closed-door gathering of House Republicans, Ryan urged them to come together so that a disruption in government programs does not overshadow Republicans' victory in passing a sweeping rewrite of the U.S. tax code.
The Republican plan currently being floated would extend government funding through Jan. 19 and provide $81 billion in disaster aid, although leaders left open the possibility of turning the latter into a separate bill.
Lawmakers said a month-long extension of a children's health insurance program and a domestic surveillance program also could be included.
Some minor military program spending increases also might be incorporated in order to win the support of "defense hawks" in the House, said Republican Representative Chris Collins, who spoke to reporters. But he did not provide details.
"I can't think of a bigger act of political malpractice after a successful tax reform vote than to shut the government down. Talk about stepping on your own message ... but anything is possible around here. This is Congress," moderate Republican Representative Charlie Dent told reporters earlier in the day.
In a possible boost for quick action on the temporary spending bill, a bipartisan Senate plan for stabilizing the Affordable Care Act, known as Obamacare, is unlikely to be included. There has been strong House Republican resistance to the idea. (Reporting by Richard Cowan; Editing by Chizu Nomiyama and James Dalgleish)