TOKONAME (Japan) • British Prime Minister David Cameron, who arrived in Japan yesterday for a Group of Seven summit, encouraged Beijing and others to abide by an impending ruling by an international tribunal on a territorial row between China and the Philippines.

Asked whether China must abide by the ruling, Mr Cameron told reporters: "We believe that it is in Britain's interests, in all our interests, to have a world that is based on adhering to the institutions of that world and the rules of that world.

"That suits us, that is good for us and it is good for the world, so we want to encourage China to be part of that rules-based world.

"We encourage everyone to abide by these adjudications and Britain has always taken that view, and I am sure that will be something that we discuss."

Tension between the Philippines and China has risen as the Permanent Court of Arbitration in The Hague prepares to deliver its ruling in the next few weeks on a case lodged by Manila in 2013 that could undermine Beijing's claims to 90 per cent of the South China Sea.

Beijing insists that the court does not have jurisdiction, arguing that any claims to the contrary are politically motivated, and has boycotted the proceedings.

But China is also a signatory to the UN Convention on the Law of the Sea.

Manila accuses Beijing of flouting the convention and has called for the tribunal, set up in 1899, to rule on the row.

In recent weeks, Beijing has lined up diplomatic battle groups over the dispute.

Niger, Togo, Afghanistan and Burundi have lent their voices to a growing diplomatic chorus that Beijing says supports its rejection of the tribunal hearing on the disputed waters.

These nations are among the latest foot soldiers in "a public relations war" by China aimed at questioning international maritime rules, said Mr Ashley Townshend, a research fellow at the United States Studies Centre at the University of Sydney.

Niger has joined the ranks of "over 40 countries that have officially endorsed China's position" that the issues should be settled through direct negotiations and not by international courts, said Chinese foreign ministry spokesman Hua Chunying.

That, she added, was just the start. "There will be more and more countries and organisations supporting China."

Similar announcements have become an almost daily ritual at China's foreign ministry media briefings as it steels itself for what is widely expected to be an unfavourable ruling.

"By cobbling together a group of nations that share its views, Beijing's aim is to show that there is a genuine debate over the legality of the Philippines' legal challenge," Mr Townshend said.

"It is trying to build a counter-narrative to push back against the mainstream international consensus on maritime law."

Despite requests by Agence France-Presse, the foreign ministry did not provide a full list of China's supporters.

But other than its main diplomatic partner Russia, few heavy-hitters have come out in support, with Beijing's neighbours - many of them unnerved by its increasingly assertive behaviour - notably absent.

Many of those disclosed so far are poor African countries, and Dr Bonnie Glaser, a senior Asia adviser at the Centre for Strategic and International Studies, described the names as "mostly composed of smaller, inconsequential nations".

Professor Zhu Feng, an international relations expert at Peking University, said: "I don't really feel that China's recent public diplomacy activities have been very successful."

Beijing, he said, "needs to develop its diplomatic activities and fight for more supporting voices".

REUTERS, AGENCE FRANCE-PRESSE