TOKYO » Japan invalidated a decision by Okinawa’s governor to stop landfill work for a controversial expansion of a U.S. base, in a move that is likely to reignite protests by islanders against the central government in Tokyo and the Obama administration.

At the core of the dispute is the planned move of the city center-based Marine Corps Air Station Futenma to the less populated Henoko area in the north of the island. Governor Takeshi Onaga, who was elected last year on a platform of opposition to the relocation plan, earlier this month revoked approval —granted by his predecessor — for the reclamation work to build a new airstrip.

The wrangling over the relocation has dragged on for nearly two decades, and is one of the few areas of tension between the governments in Tokyo and Washington. Successive Japanese administrations have struggled to fulfill alliance expectations while quelling local anger. The latest standoff — which could spur a protracted legal battle — comes amid a territorial dispute with China over islands in the East China Sea about 250 miles from the main island of Okinawa.

Okinawa is a critical part of the U.S. military presence in Asia, playing host to about half the roughly 50,000 U.S. military personnel in Japan, the biggest deployment of American forces outside the home front. While U.S. forces may offer a welcome deterrent against China’s increasing muscle, many Okinawans complain of noise, crime, pollution and accidents connected with the bases.

Following the Cabinet decision to void Onaga’s decision today, Chief Cabinet Secretary Yoshihide Suga told reporters in Tokyo that the governor has made an “illegal” move. Greenpeace Japan condemned the central government’s decision, saying in a statement that its flagship Rainbow Warrior would set sail for Okinawa this week in solidarity with opponents of the relocation.

“We stand with the majority of Okinawans who are against the expansion of this base and demand the protection of Henoko Bay and the rare and vulnerable marine life that depends on it,” the environmental organization wrote in a statement.

Onaga said last month that Okinawa alone can’t shoulder the burden of defending Japan against potential threats from China. His comments came after several discussions with Defense Minister Gen Nakatani, who said U.S. forces are needed on the island.

With most local residents opposed to the move — and a majority of respondents to a nationwide Asahi Shimbun survey earlier this year also critical of Tokyo’s handling of the issue — protests around the Henoko area are likely to swell.

“Governor Onaga may take this to trial, but I think construction can start in any case,” said Hiroshi Meguro, a research fellow at the Hosei University Institute of Okinawan Studies. “It’s possible that the demonstrations will get larger. As people start to feel there’s nothing they can do, they may also turn violent.”

The island was the site of one of the bloodiest battles between U.S. and Japanese forces during World War II. Okinawa also served as a vital staging point for U.S. troops during the Korean and Vietnam wars and administers uninhabited islets also claimed by China.

Suga, who doubles as minister in charge of reducing the military burden on Okinawa, will fly to Guam later this week, where he may discuss the partial transfer of U.S. forces to the Pacific island.