The top US navy commander vowed Wednesday to continue patrols in the South China Sea which have angered Beijing, after an international tribunal dismissed the Asian giant's vast maritime claims.

"The US Navy will continue to conduct routine and lawful operations around the world, including in the South China Sea," John Richardson said while visiting a navy base in northern China.

The sea has become a stage for rivalry between the two powers, with Washington in recent months sending navy vessels close to islands and outcrops claimed by China, provoking anger in Beijing.

"US forces will continue to sail, fly and operate wherever international law allows," Richardson said, according to an account released by Washington.

The remarks came a week after the Permanent Court of Arbitration in The Hague ruled there was no legal basis for Beijing's claim to nearly all the Sea, embodied in a "nine-dash line" dating from 1940s maps.

China rejected the verdict as "waste paper" and asserted its right to establish an Air Defence Identification Zone (ADIZ) controlling flights over the sea.

Unlike Beijing, Washington has not ratified the UN Convention on the Law of the Sea (UNCLOS) under which the tribunal ruled. But it has urged China to respect the verdict.

Chinese navy commander Wu Shengli told Richardson on Monday that Beijing would press ahead with construction in the disputed Spratlys, where it has built artificial islands on top of reefs and outcrops.

Washington has sailed warships within 12 nautical miles of some of them -- the normal territorial limit around natural land -- with Beijing citing the operations to accuse the US of "militarising" the region.

Last month China's President Xi Jinping took an apparent stab at the US patrols, saying: "We will not show up at other people's front doors to flex our muscles. That does not show strength or scare anyone."