WASHINGTON ― Delegates negotiating a vast Pacific free-trade agreement have failed to reach a final deal after several days of intense talks in Hawaii, dealing a setback to U.S. President Barack Obama.

The delay complicates his efforts this year to secure the historic accord, which risks becoming dragged into the 2016 presidential election debate.

U.S. Trade Representative Michael Froman, in a statement late Friday on behalf of the 12 countries involved in the talks on the island of Maui, insisted that significant progress had been made on the Trans-Pacific Partnership agreement, the most ambitious trade deal in decades.

“After more than a week of productive meetings we’ve made significant progress and will continue on resolving a limited number of remaining issues, paving the way for the conclusion of the Trans-Pacific Partnership negotiations,” Froman told a press conference.

Negotiators were “more confident than ever that the TPP is within reach,” he said, adding that the Pacific Rim countries would continue bilateral discussions to try and iron out remaining differences.

Already eight years in the making, TPP would be a huge bloc encompassing 40 percent of global trade and part of Obama’s much-vaunted “pivot” towards Asia in the face of an increasingly assertive China, which is not included in TPP.

The press conference was delayed several hours as the countries attempted to thrash out a deal in what had been billed as the home stretch.

The failure by trade ministers to wrap up the accord Friday was a blow to Obama ― who faces opposition to the deal from fellow Democrats ― as it could see the TPP become campaign fodder ahead of November 2016 elections.

“This setback to the TPP in Maui shifts the momentum in the national debate,” said House Democrat and accord opponent Rosa DeLauro.

“The impasse highlights very troubling issues for anyone concerned about the future of the American middle class.”

The TPP countries ― Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore, Vietnam and the U.S. ― have faced criticism for carrying out their negotiations in what opponents have charged is intense secrecy.

Its many critics say the proposals indicate a deal moving more toward protection than free trade; one more about corporate benefits than boosting economies and development.

But backers say the modern global economy needs new rules of the road to protect intellectual property-dependent 21st century industries not covered in traditional free-trade forums like the World Trade Organization.

Trade ministers were keen to talk up the positives.

“Good progress was made this week, but a number of challenging issues remain, including intellectual property and market access for dairy products,” said New Zealand’s Tim Groser, touching on two of the outstanding sensitive issues.

Akira Amari, Japan’s minister in charge of TPP negotiations, told reporters it would take another ministerial-level meeting to clinch the deal.

“According to my understanding, it is our common view that we will hold a meeting by the end of August,” Amari said, according to public broadcaster NHK.

“If we can’t conclude it next time, it’s going to be very hard.”

Australian Minister for Trade and Investment Andrew Robb said they were “on the cusp,” with “provisional decisions on more than 90 percent of issues.”

Several prickly issues were believed to have held up the talks this week, including differences over agricultural markets, auto trade and protection for drug-makers.

Also under negotiation are better copyright protection, workers rights and environmental protections.

Lawmakers who wrote the legislation giving the U.S. Congress a final up-or-down vote on TPP were cautiously upbeat about the latest round.

“While our trade negotiators were able to make significant progress this week, it is important that the United States stood firm to ensure America secures the best deal from our international trading partners,” Republican Senate Finance Committee chairman Orrin Hatch said.

But delays could put trade front and center in the election debate.

“Unless something happens it might get pushed to 2016 and become an issue that all candidates for president, for Senate, for the House are going to contend with more directly in the races,” Justin Krebs, campaign director for MoveOn.org Civic Action which is part of the anti-TPP coalition, told AFP.

“That just gives the growing progressive movement and the growing anti-corporate movement more time to make a case.”

Most of the 17 Republican candidates have signaled their backing for Obama’s trade push.

Democratic frontrunner Hillary Clinton is sitting on the fence, while her top nomination rivals Bernie Sanders and Martin O’Malley are opposed. (AFP)