SYDNEY, Jan 21 (Reuters) - Australia said it would provide A$580 million ($420 million) to Pacific neighbour Papua New Guinea to upgrade key ports, amid concern in Washington and Canberra that China's infrastructure investment in Pacific islands had a military ambition.

Earlier this month, U.S. Indo-Pacific coordinator Kurt Campbell said the Pacific may well be the part of the world most likely to see "strategic surprise", in comments apparently referring to possible Chinese ambitions to establish military bases on Pacific islands.

Australia's funding will assist the Papua New Guinea Ports Corporation to increase capacity to accommodate larger ships, including container ships on major trade routes, which will improve trade connectivity, Australia's foreign minister Marise Payne said in a statement.

The funding would also go towards urgent repairs on coastal wharves that are up to 70 years old.

A Chinese-funded wharf built on another Pacific island, Vanuatu, sparked Australian media reports in 2018 - denied by Vanautu and Beijing - that China would seek to use the facility for military ships.

($1 = 1.3904 Australian dollars) (Reporting by Kirsty Needham; Editing by Tom Hogue)