US President Barack Obama and Australian Prime Minister Kevin Rudd on Monday stressed the importance of completing the Trans-Pacific Partnership (TPP) negotiations.

The two leaders discussed the TPP and bilateral ties in their phone conversation, as Rudd returned to the premiership on Thursday following his victory in a ruling Labor Party caucus ballot the evening before, in which Rudd beat Julia Gillard,then head of the party and the prime minister.

"The two leaders also discussed the importance of completing the high standard Trans-Pacific Partnership agreement," the White House said in a statement.

The TPP negotiations involve 11 nations on either side of the Pacific. If the talks conclude successfully as expected before the APEC summit begins in October, the largest free trade zone will be created in the world.

In his phone talks with Rudd, Obama also reiterated the " enduring strength" of the US-Australia alliance and his confidence that the two countries will continue to work closely on "important global and regional issues," the White House said.

Obama made the call on Air Force One en route to Tanzania, his last stop in his current tour of Africa, which has taken him to Senegal and South Africa.

Rudd served as prime minister from 2007 to 2010.