The US has secured access to four additional military bases in the Philippines - a key bit of real estate which would offer a front seat to monitor the Chinese in the South China Sea and around Taiwan.

The statement came after Defence Secretary Lloyd Austin met Philippine President Ferdinand "Bongbong" Marcos Jr in Manila on Thursday.

"There is no contingency in the South China Sea that does not require access to the Philippines," says Gregory B Poling, director of the Southeast Asia programme at the Centre for Strategic and International Studies in Washington.

That is, it is seeking access to places where "light and flexible" operations involving supplies and surveillance can be run as and when needed, rather than bases where large numbers of troops will be stationed.

In other words, this is not a return to the 1980s, when the Philippines was home to 15,000 US troops and two of the largest American military bases in Asia, at Clark Field and nearby Subic Bay.

Since 2014 China has built 10 artificial island bases, including one at Mischief Reef, deep inside the Philippines' own exclusive economic zone or EEZ.