US President Barack Obama on Wednesday suggested that China could eventually join a nascent trans-Pacific trade pact, raising the prospect of an accord spanning much of the globe.

With talks nearing completion for the 12-member Trans-Pacific Partnership, Obama hinted that the leaders of the world's second largest economy could jump on board.

"They've already started putting out feelers about the possibilities of them participating at some point," he told Marketplace, a radio program.

Although China's membership does not appear to be imminent, Obama's comments raise the prospect that the trans-Pacific deal could be a building block for a broader agreement.

The deal includes large economies like Japan, South Korea, Vietnam, Canada and Australia and a similar US-European Union accord is also being discussed.

But major hurdles remain, including for Obama at home.

The White House is currently struggling to gather enough votes in Congress to grant Obama trade negotiating powers.

The prospect of China one day joining is likely to exacerbate concerns among Obama's own Democrats about labor standards and US jobs moving overseas.