WASHINGTON (Reuters) - A fractured U.S. Congress struggled behind the scenes on Wednesday to produce a massive spending bill to fund defense, homeland security and other programs that lawmakers must pass before the weekend to avert a partial government shutdown.

Republican House of Representatives Speaker Mike Johnson and other House Republican leaders said they hope to vote on Friday, leaving the Democratic-majority Senate just hours to meet a midnight deadline by passing legislation that is expected to cover about three-fourths of the $1.66 trillion in discretionary government spending for the fiscal year that began on Oct. 1.

Johnson said he hoped legislation would be unveiled as soon as Wednesday but warned that a vote on passage would be delayed to give lawmakers time to review the measure.

House and Senate Republicans are also discussing a possible short-term continuing resolution, or "CR" - their fifth since September - to keep federal agencies funded at current levels until after a two-week congressional break that is expected to begin on Friday.

"We should have the bill text - hopefully - by this afternoon," Johnson said on Wednesday, as the window for action narrowed. "I don't think we'll need a CR - I don't."

Two weeks ago, Congress narrowly avoided a shutdown that would have affected agricultural, transportation and environmental programs, without resorting to a CR.

Johnson and Democratic Senate Majority Leader Chuck Schumer unveiled an agreement on funding on Tuesday morning, and Democratic President Joe Biden pledged to sign it into law.

More than 24 hours later, congressional leaders were still unable to release the legislation as aides worked behind closed doors to finalize the text of the package, prompting hardline Republicans to complain they may not have enough time to review the legislation.

"We're told to pass the bill unread, not understood and debated, or, alternatively, face the chaos and inevitable public vitriol associated with a government shutdown," said Senator Mike Lee, a hardline Republican from Utah, who backs a CR to April 12 to give lawmakers time to review the text.

House Republicans could waive their policy of waiting 72 hours before bringing legislation to the floor, not only to avert a shutdown but to head off an exodus of lawmakers on the eve of the two-week recess.

Besides the departments of Homeland Security and Defense, the bill would fund agencies including the State Department and the Internal Revenue Service as it girds for its April 15 taxpayer filing deadline.

But more political battles lie ahead as the nation's $34.5 trillion national debt continues to grow.