WASHINGTON, Oct 5 (Reuters) - The Senate will vote on Wednesday on a Democratic-backed measure to suspend the U.S. debt ceiling, a key lawmaker said on Tuesday, as partisan brinkmanship in Congress risks an economically crippling federal credit default.

Senate Majority Leader Chuck Schumer said that senators will hold a procedural vote on the bill - opposed by Republicans - to suspend the borrowing limit through the end of 2022. Treasury Secretary Janet Yellen has told lawmakers that the government would exhaust its borrowing capabilities by about Oct. 18 if they do not act.

"We can resolve the debt ceiling crisis this week and reassure the world that the full faith and credit of the United States will never be in question," Schumer said on the Senate floor.

President Joe Biden's fellow Democrats narrowly control both chambers of Congress. The House of Representatives passed the debt ceiling legislation last week. The measure needs 60 votes to advance in the evenly divided 100-seat Senate.

Republicans are vowing to block it as part of their strategy to impede Biden's ambitious social spending agenda ahead of the 2022 congressional elections.

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Senate Minority Leader Mitch McConnell has called upon the Democrats to address the debt ceiling on their own through a procedure known as budget reconciliation, which would require no Republican votes. Senate Republicans have twice blocked Democrats from seeking bipartisan support for addressing the debt ceiling.

A first-ever default on the federal debt could impose dire consequences on the U.S. economy by eliminating millions of jobs, throwing financial markets into turmoil and raising the cost of home mortgages and business loans, according to analysts.

Without a quick resolution, some government services might be suspended, such as delivering Social Security benefit checks to the elderly.

Biden and Schumer have rejected reconciliation as too convoluted and risky for addressing the debt ceiling issue and have warned of economic catastrophe unless Republicans change course.

"If Republicans want to vote 'no' tomorrow, if they really want to be the party of default, that's their choice," Schumer said. "They have a chance to show that they're still responsible. It's not too late. But it's getting dangerously close."

Schumer wants Republicans to simply allow the Senate to debate and hold a final vote on a debt limit suspension.

At least 10 Republicans would need to join the Senate's 48 Democrats and two independents who caucus with the Democrats to achieve the 60-vote threshold, which would enable the Democrats to pass the bill with a simple majority later in the week.

Republicans, hoping to make Democrats solely responsible for a higher debt ceiling, have rejected any possibility of lending a hand.

"The majority doesn't need our votes. They just want a bipartisan shortcut around procedural hurdles they can clear on their own," McConnell said on Monday.

Some Republicans have said that the reconciliation path could consume the attention of Congress, further slowing Biden's ability to reach agreement on his multitrillion-dollar social agenda and potentially undermining his support among moderates.

It also would require Democrats to adopt a specific dollar figure for a new, higher debt ceiling on their own, which Republicans could then target with 2022 election campaign attack ads centering on the issue of fiscal responsibility.

(Reporting by David Morgan; Editing by Will Dunham)