The US will partner with Australia to redevelop Papua New Guinea's naval base at Manus Island, dramatically ramping up the American presence in the South Pacific in a check on Chinese ambitions to expand its strategic influence.

Vowing to keep sea lanes open, US Vice President Mike Pence announced the partnership with Australia and Papua New Guinea to redevelop the Lombrum naval base at the Asia-Pacific Economic Cooperation summit in his keynote address to business leaders in Port Moresby.