A collection of top House and Senate Democratic aides convened a meeting Wednesday of a bipartisan group of about 30 business lobbyists to send a message to corporate America: Democrats will not pass a much-prized tax cut extenders package unless it is paid for by tax increases.

Those are fightin’ words for Republican Members, who have blocked the tax package because it includes an offset to pay for the roughly $50 billion in tax break extensions — primarily by delaying tax cuts for interest earned overseas and eliminating deferred compensation in some offshore accounts.

The vast majority of the business community does not oppose those obscure offsets. And they certainly crave the extenders, which include popular tax credits for research and development and renewable-energy programs.

Just last week, Republican Senate leaders had a meeting of their own where they reiterated their support for the tax extenders but also reiterated their opposition to the offsets currently in the bill.

Democratic sources said their party’s meeting, held at 1 p.m. in Hart Senate Office Building, was scheduled to counter the Republican confab of last week.

“The Republicans say they’re not budging, and the Democrats say we’re not blinking,” said one lobbyist who attended the Wednesday afternoon meeting. “Both sides are digging in, and the business community is getting increasingly frustrated.”

Staffers who led the meeting were Gary Myrick, chief of staff to Senate Majority Leader Harry Reid (D-Nev.); Janice Mays, staff director for the House Ways and Means Committee; Russ Sullivan, staff director of the Senate Finance Committee; Ed Lorenzen, a senior aide in the office of House Majority Leader Steny Hoyer (D-Md.); and another Reid aide, Bob Greenawalt.

Some of the lobbyist attendees included Jimmy Ryan of Citigroup; Chuck Brain, who runs Capitol Hill Strategies; Capitol Tax Partners’ Lindsay Hooper; Charles Mellody of the OB-C Group; and in-house representatives from several U.S. corporations.

A second lobbyist who attended the meeting said the business community needs to ramp up its pressure on Congressional Republicans who oppose the extenders bill and to show lobbyists that, counter to the message of GOPers, Democrats are unified on the matter.

“Part of it was so that people downtown understand that when they hear from Republicans, ‘Don’t lobby us on this; we’re making progress,’ that’s not happening,” the second lobbyist said. “This thing is going to be paid for, and if the business community wants it, they better get on board.”

This lobbyist added that the Republicans’ meeting last week, where Senate leaders urged their allies in the lobbying profession to stick with them on the issue, is “symbolic of what’s wrong with this town.”

“Most of K Street is still controlled by Republicans, who are more interested in doing Republicans’ bidding than in representing their companies,” the lobbyist said.

A third lobbyist who attended the session said the House and Senate Democrats stressed the importance of the tax extenders bill, and that corporate America should back the Democrats’ plan.

This lobbyist said the staffers told the group: “We’re not kidding you. House and Senate Democrats are united on the need to pay for them, so you better start acting on that basis.”

The first lobbyist added that the broad business community is becoming increasingly jittery about the fate of the popular R&D and renewable-energy tax extenders.

“It’s getting to the point where companies are starting to lose deals,” this lobbyist said. “Renewable energy projects are starting to go offshore. Leasing deals are being lost. Some people won’t make commitments on R&D projects. It’s starting to have a significant economic impact.”