US President Barack Obama. File photo: Jacquelyn Martin

Washington - The Obama administration on Wednesday moved to ease concerns on Capitol Hill about a proposed Pacific free trade agreement, promising lawmakers easier access to the draft text.

Critics have questioned secrecy around the 12-nation negotiations for a trade deal covering 40 percent of the world economy. Several members of Congress have complained about conditions put on access to negotiating texts.

The changes were announced at a Democratic caucus meeting with US Trade Representative Michael Froman and Treasury Secretary Jack Lew on currency manipulation, one of a series of briefings on key trade issues aimed at winning support for trade initiatives among Democrats.

Froman said the new measures would allow lawmakers to look at the full text of the Trans-Pacific Partnership (TPP) at their convenience, along with plain English chapter summaries.

“Today, working directly with Congress we have taken unprecedented additional measures to help members fully understand the benefits we are working to bring home for American workers, businesses, farmers and ranchers,” he said in a statement.

An administration official said the TPP text would be available to review in the congressional security office, without the presence of administration officials. Members can also bring a personal staff member, as long as the person has security clearance.

New Zealand Trade Minister Tim Groser, in Washington to meet US officials and lawmakers, said the TPP could not close without lawmakers passing trade promotion authority (TPA), legislation to streamline passage of trade deals.

“I think this can be done very rapidly,” he said of the TPP.

“Get TPA in place, we can do this deal.”

There have been delays in finalising the legislation, which is not expected to come before Congress until April. These delays have been blamed for pushing back the timetable for the TPP.

The bill faces a tough vote, with opposition from many Democrats and some conservative Republicans despite concerted lobbying by the administration and corporate groups.

Richard Trumka, the head of the AFL-CIO union federation, said unions were diverting campaign resources into defeating fast-track although they would be outspent by business groups.

“We'll spend what it takes - everything we can do, everything we can afford to spend, to try to defeat it,” he said at the Peterson Institute for International Economics.