Residents of Japan's Okinawa Sunday elected a governor who opposes plans to relocate a US military base within the island chain, a fresh setback in efforts to resolve a thorny issue in military relations.

Voters in the southern prefecture chose Takeshi Onaga over the incumbent Hirokazu Nakaima, Kyodo News agency reported, citing the local election board in Okinawa.

Kyodo described the victory as a "landslide" win for Onaga, who secured 360,820 votes to incumbent Nakaima's 261,076, according to Okinawa's local election board.

Onaga's apparent victory is a significant blow to the central government because the governor can veto the landfill work needed for a new base to be built.

In his first comments, the 64-year-old indicated he would do just that.

Any veto would leave Prime Minister Shinzo Abe having either to overrule locally-elected officials -- risking charges of authoritarianism -- or reverting to the cajoling and persuading of recent years, which would not be popular with Japan's close ally the United States.

It would also take some of the wind out of Abe's sails just days before he is expected to announce a snap general election.

Years of deadlock on the planned base relocation have frustrated the Americans and been a thorn in the side of successive Japanese governments.

Okinawa is home to more than half of the 47,000 US service personnel stationed in Japan, and strategically key to the US-Japan security alliance at a time of simmering tensions in East Asia.

But there is widespread local hostility to the military presence, with complaints over noise, the risk of accidents and a perception that the presence of so many young servicemen is a source of crime.

There have been plans for years to move the US Marines' Futenma Air Station from a crowded urban area to a sparsely populated coastal district elsewhere on Okinawa -- some 50 kilometres (30 miles) to the north of the current location.

But opponents like Onaga say Okinawa already hosts a disproportionate share of the US military presence in Japan, and the US base should be moved outside the islands altogether.

Incumbent governor Nakaima stands accused of betraying the islanders after striking a deal with Tokyo last year to approve the relocation within Okinawa.

In what critics said amounted to a bribe, Abe pledged a huge cash injection to the local economy in return for Nakaima reversing years of opposition to the move, which was first mooted in the 1990s.

Katsuji Miyagi 64, a retiree, told AFP he voted for Onaga.

"Four years ago I voted for Nakaima but he broke his promises," he said.

"I've had enough of these bases. I want no more bases in Okinawa."

- Bitter memories -

"I'd like to convey the message to the governments of Japan and the United States... that the wishes of the people here are different from the administrative action in December last year," Onaga told reporters, referring to his predecessor's about-face.

Onaga, quoted by Jiji Press, said he would "act with determination" towards retracting approval for the landfill work.

The current base sits in a residential district whose inhabitants bitterly recall a 2004 military helicopter crash in the grounds of a local university, and who resent the sound of roaring engines metres from their backyards.

Nakaima says the relocation plan is the only realistic option to eliminate the danger of the Futenma base.

The dispute taps into a vein of historical resentment. Previously an independent kingdom, Okinawa was annexed by Japan in the 19th century and was under US rule for almost three decades after World War II.

In talks with US President Barack Obama Sunday, Abe stressed the importance of the security alliance with Washington. He also called for US cooperation in "easing Okinawa's burden" of hosting US forces in Japan as part of a wider realignment plan, Japanese media reported.

They met on the sidelines of the Group of 20 summit in the Australian city of Brisbane.