BEIJING (AFP) - Japan on Sunday released the captain and crew of a Chinese boat who had been detained on suspicion of illegal fishing, Chinese state media reported amid a festering territorial row between the neighbours.

The 100-tonne coral fishing boat with a crew of 13 was stopped on Saturday by a Japanese coastguard patrol in waters some 45km north-east of Miyako island in the southern Okinawan chain.

The skipper and all his crew were released after the Chinese consulate general in Fukuoka submitted a bail guarantee, Xinhua news agency said, quoting the consulate general.

The fishing boat and all its crew departed Miyako for China late on Sunday, it said.

The Japanese coastguard said Saturday that the captain had been arrested on suspicion of fishing in the exclusive maritime zone without permission from Japan.

The incident occurred amid a simmering dispute over the Tokyo-administered Senkaku islands, which China also claims and calls the Diaoyus.

Miyako is about 210km off the biggest disputed isle.

The arrest was made on the same day that Japanese Prime Minister Shinzo Abe toured the southern region of Okinawa near the disputed islands in the East China Sea, where he vowed to defend Japan against "provocations".

Abe's comments came in the same week that his government approved a rise in defence spending for the first time in over a decade, explicitly aimed at beefing up defence of the contested island chain.

Chinese government ships have routinely circled the islands since September, when Tokyo nationalised some of them.

Chinese planes have also sporadically breached the airspace over them, stoking the long-running sovereignty row.

It was the first time that the captain of a Chinese fishing boat was detained in waters in the Okinawa region since September 2010 when Japan arrested a Chinese trawler captain after he rammed his vessel against two coastguard patrol boats in waters around the disputed islands, Kyodo news agency said.

The arrest sparked off a fierce diplomatic protest from Beijing and Tokyo released the captain weeks later without prosecuting him.