The Philippines said Tuesday it expects to get 10 new Japanese patrol boats within 18 months, as it tries to strengthen its sea defence capabilities amid a deepening territorial row with China.

Foreign Affairs Secretary Albert del Rosario said the boats were 40-metre (132-foot) vessels to be used by the Philippine coast guard.

"I think (their delivery) is between 12 to 18 months," del Rosario said in brief comments to reporters. He did not specify how much each boat would cost.

The Nikkei, a Japanese business daily, reported on Monday that Japan planned to donate patrol boats costing $11 million each to the Philippines, a move it linked to regional efforts to monitor China's maritime activity.

Japan and the Philippines are embroiled in separate territorial disputes with China.

The Philippines' dispute with China involves overlapping claims to parts of the South China Sea, which is believed to sit above vast amounts of oil and gas.

China claims most of the South China Sea, including waters approaching the coast of the Philippines and other Southeast Asian countries.

Tensions between China and the Philippines escalated dramatically in April last year when vessels from both countries became locked in a standoff at Scarborough Shoal, a rich fishing ground.

The shoal is about 230 kilometres (140 miles) west of the Philippines' main island of Luzon. The Philippines says that China has maintained vessels at the shoal to bolster its claim, reneging on an agreement to pull them out.

The Philippines has conceded its poorly equipped navy and coast guard are of little deterrence to China.

Their fleets are made up mostly made up of ageing, second-hand vessels, many of which date back to World War II.