Okinawa Governor Takeshi Onaga said on Monday that he will revoke previous approval granted for land reclamation as the prefectural government in southernmost Japan continues efforts to block the relocation of a controversial US airbase on the island.

Onaga - a staunch opponent of the accord between Japan and the US to relocate the US Marine Corps' Futenma Air Station from the densely populated region of Ginowan to the coastal Henoko region - told local media that the decision had been made to repeal approval for landfill work based on a legal flaw found in the approval process.

"It has been recognized that the approval has defects," Onaga was quoted by local media as saying at a news gathering earlier on Monday.