The Philippines has halted the repair of its airstrip in the disputed Spratly islands due to its pending suit at The Hague challenging China's claim over the waters, a presidential spokesman said Sunday.

The work on the airstrip on Thitu island, which the Philippines calls Pagasa and which hosts a small community, comes as China builds up outcroppings in the waters into islands that can host military facilities.

"The repair has been stopped because we uphold the principle of keeping the status quo in the areas involved," said President Benigno Aquino's spokesman Herminio Coloma.

"This is part of our strategy for a rules-based and diplomatic approach where we have filed an arbitration case with the UN tribunal," he added.

The tiny airstrip on Pagasa had been largely used to bring in supplies for the small town that the Philippine government established there to stake its claim over part of the Spratlys.

However the airstrip has deteriorated over the years, forcing the government to rely on ships which must go through a gauntlet of Chinese vessels to reach the island.

China claims almost all of the Spratlys and the South China Sea, even areas close to the coasts of its neighbours. Its claim is disputed by the Philippines as well as Brunei, Malaysia, Vietnam and Taiwan.

The waters are a crucial sea lane and rich fishing ground also believed to hold large mineral resources.

In 2013 the Philippines asked The Hague, based in the Netherlands, to declare China's claim invalid and in violation of international law.

Hearings -- looking at whether Manila's complaint has legal merit as well as whether the court has jurisdiction over the case -- are set to begin next month.