MANILA The Philippines and China have agreed to set up new lines of communication to improve their handling of maritime disputes, according to a document and a Philippine diplomatic source, as ties sour over clashes about territory in the South China Sea.

The two countries have traded barbs repeatedly over jurisdiction in the contested South China Sea as the Philippines, emboldened by support of defence ally the US, challenges China's permanent presence around strategic features inside Manila's exclusive economic zone (EEZ).

Three communication channels would be established specifically for maritime issues, according to the source, who provided a document with highlights of an "Arrangement on Improving Philippines-China Maritime Communication Mechanisms", which was signed during regular talks between them on July 2.

The foreign ministries of China and the Philippines and the Chinese embassy in Manila did not immediately respond on Wednesday to separate requests for comment on the matter.

The first channel would be used by "representatives to be designated by their leaders," with the other for respective foreign ministries at ministerial or vice-ministerial level, or their designated representatives, according to the document.

The third would involve their respective coast guards "which will be set up once the corresponding MOU [memorandum of understanding] between the coast guards is concluded," the document said.

The source, who declined to be identified because they were not authorised to speak on the issue, said the Philippine foreign ministry was discussing with its Chinese counterpart guidelines to govern the implementation of the arrangement, which follows a June 17 clash between rival vessels near the Second Thomas Shoal, the site of frequent standoffs.

The Philippines last month accused China's coast guard of intentionally ramming and deliberately puncturing navy boats and seizing weapons to disrupt a resupply mission to troops stationed on the vessel grounded at the shoal, seriously injuring a Filipino sailor who lost a finger.

China said the Philippine vessel had illegally intruded on its territory and had "deliberately and dangerously" approached a Chinese ship resulting in a slight collision.

The agreement on communications channels is not the first, with the two sides establishing a line between respective maritime offices.

They agreed during the recent bilateral meeting on the need to "restore trust" and "rebuild confidence" to better manage disputes.

The Philippine resupply missions, often accompanied by media, have riled China, which sees the Second Thomas Shoal as part of its territory, despite being 1,300km (808 miles) off its mainland and within Manila's EEZ.

Beijing maintains it has sovereignty of most of the South China Sea based on its old maps and has deployed hundreds of coast guard vessels deep into Southeast Asia to assert its claims, disrupting offshore energy and fisheries activities of other neighbours, including Malaysia and Vietnam.

China has refused to recognise a 2016 international arbitral ruling that concluded Beijing's claims have no basis under international law.

The US has backed the Philippines over the clashes, condemning what it calls Chinese aggression, while underlining its "ironclad" commitment to a 1951 Mutual Defence Treaty under which it must defend its former colony if attacked. China has accused the US of interference.

While China claims almost all of the vital waterway, where US$3 trillion worth of trade passes annually, the Philippines, Brunei, Malaysia, Taiwan and Vietnam lay claims to parts.

  - Reuters