WASHINGTON - The Obama administration on Friday invited 12 Democratic members of Congress and nine Republicans to a February 25 conference on healthcare and said it would post its proposal for a legislative overhaul online before the event.

President Barack Obama has asked Republicans to bring their best healthcare ideas to the conference on revamping the $2.5 trillion U.S. healthcare system. The issue, critical to his domestic agenda, has floundered since Democrats lost their crucial 60th Senate vote last month, in the face of united Republican opposition and public skepticism.

The meeting will be broadcast live, answering criticism that the Democratic president did not engage Republicans and instead negotiated backroom deals in an effort to get legislation passed.

The invitation letter said the White House will post the text of its proposed health overhaul package online before the meeting, and invited Republican leaders to post their own bill online as well.

Now is the time to act on behalf of the millions of Americans and small businesses who are counting on meaningful health insurance reform, said the formal invitation, from Rahm Emanuel, Obama's chief of staff, and Kathleen Sebelius, secretary of health and human services.

Republican leaders have said they will attend, but expressed skepticism about whether Obama will work with them.

The existence of any kind of backroom health care deal among the White House and Democratic Leaders would certainly make a mockery of the President's stated desire to have a 'bipartisan' and 'transparent' dialogue on this issue, House Republican leaders wrote in a letter to House Speaker Nancy Pelosi and Senate Majority Leader Harry Reid on Friday.

OUT WITH THE OLD?

Republicans have called for healthcare bills crafted by the House of Representatives and Senate, after six months of tough compromises by Obama's fellow Democrats, to be thrown out.

The White House has said it does not intend to do so, and the invitation seemed to confirm that. In the last year, there has been an extraordinary effort to craft effective legislation, it read, referring to hundreds of hours of activity in both the House and Senate on the two bills.

The Blair House meeting is the next step in this process, the letter said.

Senate Republican leader Mitch McConnell said his party would continue to offer the types of ideas and step-by-step approach to cut costs and increase coverage without cutting benefits for older Americas or raising taxes.

He said the Republicans would consult with the White House about the meeting format and topics, but made clear they were ready for a fight.

Nearly one year ago, the President moderated a health care summit that kicked off a national debate that has led us to where we are today: a partisan bill devoid of support from the American people and a diminished faith in this government's capacity to listen, he said in a statement.

Let us not make the same mistake twice.

With about 46 million people lacking health insurance, polls show a high level of frustration as Americans watch the abortive reform process at a time of economic crisis and high unemployment that has eroded support for Obama. Obama's Democrats are under pressure to produce results before elections in November in which the entire House and more than a third of seats in the Senate will be up for grabs.

The administration's letter invited Democrats Pelosi and Reid, McConnell and House Republican Leader John Boehner, and asked each to designate four other members of Congress to participate.

The invitation list also includes Democratic and Republican leaders of the Senate Finance Committee; Senate Health, Education, Labor and Pensions Committee; House Ways and Means Committee; House Energy and Commerce Committee, and the House Education and Labor Committee, all of which oversaw the health legislation in both chambers.

The White House said Obama, Vice President Joe Biden, Sebelius, and Nancy-Ann DeParle, director of the Office of Health Reform, would also attend.

Obama will make opening remarks, followed by remarks from a Republican leader and a Democratic leader chosen by leaders of their parties, and then the president will open discussion on insurance reform, cost containment, expanding coverage and the effect of health reform legislation on deficit reduction.

(Additional reporting by Steve Holland; Editing by Eric Walsh)