Japan pledged Thursday to help the Philippines defend its "remote islands", as both governments expressed concern over China's robust moves to stake its claims to disputed Asian waters.

Japanese Defence Minister Itsunori Onodera said China's contentious claim to nearly all of the South China Sea and its territorial dispute with Japan in the East China Sea were discussed during top-level talks in Manila.

"We agreed that we will further co-operate in terms of the defence of remote islands... the defence of territorial seas as well as protection of maritime interests," Onodera told a joint news conference.

"We face a very similar situation in the East China Sea of Japan. The Japan side is very concerned that this kind of situation in the South China Sea could affect the situation in the East China Sea," he said, speaking through an interpreter.

Philippine Defence Secretary Voltaire Gazmin welcomed Japan's offer of support for its poorly resourced military.

"We have agreed to continue our exchanges of information, exchanges of technology to help each other to make our defence relations stronger," Gazmin said.

Neither side offered specifics but Philippine Foreign Affairs Secretary Albert del Rosario said in February his country was expecting to get 10 new Japanese patrol boats within 18 months.

The Japanese military brutally occupied the Philippines during World War II, but the two countries have since grown closer due to trade and investment, and more recently, through China's assertiveness.

Del Rosario told the Financial Times newspaper in December that a rearmed Japan would help the region counter-balance China.

Onodera and Gazmin also on Thursday welcomed an increased military presence in Asia by their mutual ally, the United States.

However Onodera said Japan was intent on avoiding conflict with China.

"I would also like to emphasise here that the current situation should not be changed with the use of force but should be done through the rule of law," Onodera said.

China claims most of the South China Seam including waters close to its neighbours' coasts. The Philippines, Brunei, Malaysia, Vietnam and Taiwan also have competing claims.

The Philippines has complained of increased Chinese "bullying" in the contested waters in recent years, and infuriated China by appealing to allies Japan and the United States for help.

The Philippines says China last year occupied an atoll well within the Filipino exclusive economic zone.

Tensions between China and Japan have also escalated over competing claims to the Japanese-held Senkaku islands, which Beijing calls the Diaoyus, in the East China Sea.