WASHINGTON, March 27 — Prospects for Congressional approval of several pending trade pacts received a surprising lift on Tuesday when Democrats in the House proposed a series of revisions that won guarded praise from both organized labor and the Bush administration.

The Democratic proposals would require that the trade accords include provisions protecting the rights of workers, the environment and the right of trading partners to make cheap generic pharmaceuticals for use in their countries, all of which had previously been resisted by the administration.

Charles B. Rangel, the New York Democrat who is chairman of the House Ways and Means Committee, won approval of the proposals from the House speaker, Nancy Pelosi, and other leading Democrats by using language aimed at strengthening these rights while trying to meet some administration concerns.

What was unusual about the proposals is that they were praised by the A.F.L.-C.I.O. as an improvement of the pending deals with Colombia, Panama and Peru and a pact being negotiated with South Korea.

The proposals were also welcomed by the United States trade representative, Susan C. Schwab.

Ms. Schwab hinted that the administration might seek to make some changes in the Democrats' proposals, which were embodied in a 15-page document submitted to her office but not released to the public.

But Republicans, speaking anonymously, said the administration would have little choice but to accept the broad outlines of the Democrats' proposals if it wanted to win passage in a Democratic-controlled Congress.

"This is another step in what has been a good-faith effort in a continuing dialogue by all sides," Ms. Schwab said. She is expected to meet with Mr. Rangel and Representative Jim McCrery of Louisiana, the ranking Republican on the Ways and Means Committee, with a goal of reaching an accord before the end of the week. Mr. McCrery also welcomed the Democrats' proposals.

Mr. Rangel said that he believed the negotiations would be successful.

"There may be some things I don't know about that they won't like," he said. "But I don't know of any objections that can't be worked out. The thing is, everyone is pretty upbeat about this."

By themselves, the accords on Colombia, Peru and Panama are not considered economically significant. But Democrats and Republicans in Congress see them as a test for what the administration might be willing to accept in future trade deals.

The administration, for example, hopes to salvage a global trade deal in coming months that would lower tariff barriers in 180 countries worldwide, allowing the United States to export financial services, manufactured goods and farm products to scores of countries that now have tariffs or other barriers.

The global deal under the so-called Doha round of negotiations — named after the city in Qatar where the talks started several years ago — has been stalled for nearly a year. Also pending is the request of President Bush that his own authority to negotiate trade deals and get an up-or-down vote in Congress be extended beyond its current expiration date of June 30.

The administration must submit trade deals at least 90 days before the expiration of that authority, which means that any changes in the Latin American trade pacts, and also in the one being negotiated with South Korea, would have to be submitted with the changes sought by Democrats this week.

Some lawmakers say that whatever is agreed to on these deals could provide a template for the other deals, opening the possibility for more to be approved even at a time when the administration and Democrats are at odds on a range of budget, tax and economic regulatory policies.

In addition, Democrats say that even if Ms. Pelosi, Mr. Rangel and other party leaders in the House support the Latin American or South Korean deals, a large number of Democrats in the House and Senate would most likely oppose them on principle.

In the Senate, for example, several newly elected freshmen ran on campaigns calling for no more trade deals under the Bush administration. On the other hand, Mr. Rangel and Ms. Pelosi are under pressure from Wall Street, the high-technology industry and other economic sectors to support lower trade barriers.

Mr. Rangel said he understood that no matter what, some Democrats will oppose trade deals, and that some Republicans will as well.

"There's going to be a coalition vote for trade with moderates in both parties in support," he said. "We are not going to have an appeal to the extremes like we've had in the past. I think the moderates are going to give a larger vote than ever for trade."