UPDATE 1-Obama not making new 'fiscal cliff' offer to Congress-source

WASHINGTON, Dec 28 (Reuters) - President Barack Obama was not planning to make a new offer to avert the tax increases and spending cuts that loom on Jan. 1 at a White House meeting with congressional leaders on Friday, a source familiar with the meeting said.

At the meeting, Obama was set to ask lawmakers to hold a vote on a "fiscal cliff" plan that would allow taxes to rise on those who earn $250,000 and up, and that would extend unemployment insurance benefits, according to the source.

Obama believes his plan would pass with a majority in both the House of Representatives and the Senate, the source said.

The president was meeting with Senate Majority Leader Harry Reid, Senate Minority Leader Mitch McConnell, House Speaker John Boehner and House Minority Leader Nancy Pelosi - the first time the group has met together since November.

If congressional leaders object to his plan, Obama will ask them for a viable counterproposal, the source added. If lawmakers have no alternative approach, he will seek an up-or-down vote in Congress on his plan, the source said.