Manila: The United States will upgrade and build facilities on Philippine military bases this year, Manila's defence minister said, bolstering an alliance strained by President Rodrigo Duterte's opposition to a US troop presence.

The Pentagon gave the green light to start the work as part of an Enhanced Defence Cooperation Agreement (EDCA), a 2014 pact that Duterte has threatened to scrap during barrages of hostility towards the former colonial power.

Philippine President Rodrigo Duterte salutes the honour guard. Credit:AP

"EDCA is still on," Defence Secretary Delfin Lorenzana told a news conference on Thursday.

EDCA allows the expansion of rotational deployment of US ships, aircraft and troops at five bases in the Philippines as well as the storage of equipment for humanitarian and maritime security operations.