The Trans-Pacific Partnership (TPP), a centerpiece of Obama's strategy to counter China's rising economic and diplomatic clout in Asia, will create a free trade zone covering 40 percent of the world economy.

Australia's minister for trade and investment, Andrew Robb, said only one more negotiation round was needed to finalise the TPP once both the U.S. Senate and House of Representatives pass the Trade Promotion Authority bill (TPA), granting U.S. President Barack Obama the power to speed the trade pact.

"I think it is at an advanced stage. But it could well be delayed until June, before the House gets to pass it through. That is still not life or death," Robb said of the TPA bill.

After the TPA bill passed through the House in June, there would be another round of negotiation on the Pacific trade pact, he added.

"We will have another negotiation, and we could well conclude it in June," Robb told Reuters on the sidelines of a business mission in Manila, in a reference to the Pacific pact.

There were a "few very difficult issues" that needed to be resolved by each of the 12 TPP countries, but talks were at an advanced stage, Robb said.

The issues concerning Australia involved the pharmaceuticals sector, and those related to dispute settlement and market access, he added.

"None of it is a dealbreaker really, but it is important," he said.

The U.S. Congress is rushing to close debates on the fast-track bill ahead of a 10-day Memorial Day recess at the week's end.

Apart from the United States and Australia, other countries in talks to form the TPP are Japan, Canada, Mexico, Peru, Chile, Vietnam, Malaysia, Singapore, Brunei, New Zealand. (Reporting by Rosemarie Francisco; Editing by Clarence Fernandez)