TOKYO (AFP) - The governor of Japan's Okinawa on Tuesday (Oct 13) revoked approval for work on a United States air base on the southern Japanese island, in the latest setback to the controversial plan.

The proposal to relocate Futenma air base to the Henoko region, first mooted in 1996, has become the focus of anger among locals, who insist it should be shut and a replacement built elsewhere in Japan or overseas.

Outspoken Okinawa Governor Takeshi Onaga voided approval after work in Henoko resumed last month following a month-long delay, saying that "defects" had been found in the approval given by his predecessor in 2013.

"We will do our best to fulfil my promise not to build a new base in Henoko," Mr Onaga told a news conference in Okinawa.

Work in Henoko, a rural coastal district in central Okinawa chosen for the replacement facility, is only in the initial stages with crews setting up sea floats and a makeshift bridge necessary for landfill work.

The move by the governor leaves the future of construction of the new base in doubt, with the authorities on the sub-tropical island and the central government likely to take their dispute to court, local media reported.

Okinawa is home to more than half of the 47,000 US service personnel stationed in Japan as part of the two countries' defence alliance, a proportion many islanders say is too high.

There is widespread agreement that Futenma's current site - in the middle of a crowded urban area where US aircraft are a nuisance to thousands of locals - is not appropriate.

But the US says it will not close the base until a replacement facility is ready.

The central government on Tuesday said it had no plans to halt construction at Henoko, with Chief Cabinet Secretary Yoshihide Suga adding that it would consider taking counter-measures to reverse the revocation.

"Voiding approval for the reclamation... ruled out the efforts made by Okinawa and government officials to remove the danger of Futenma," Mr Suga told a news conference in Tokyo. "I feel it is quite regrettable."

The move comes after demonstrators staged a series of rallies in Tokyo and Okinawa to protest against the construction in Henoko, where environmentalists say any development risks seriously damaging nearby coral reefs and the delicate habitat of the dugong, a rare sea mammal.

Both Tokyo and Washington have repeatedly backed the plan, with Prime Minister Shinzo Abe last month insisting it was "the only solution".