TOKYO (Reuters) - The U.S. Pacific Fleet Commander has warned of a possible arms race in the disputed South China Sea which could engulf the region, as nations become increasingly tempted to use military force to settle territorial spats instead of international law.

Commander Admiral Scott Swift urged nations, like China, to seek arbitration to settle maritime disputes.

“My concern is that after many decades of peace and prosperity, we may be seeing the leading edge of a return of “might makes it right” to the region,” Swift said on Monday in a speech in Hawaii, according to a copy seen by Reuters.

“Claimants and non-claimants alike are transferring larger shares of national wealth to develop more capable naval forces beyond what is needed merely for self defence,” Swift said.

Asked about Swift’s comments, Chinese Foreign Ministry spokesman Hong Lei said: “Certain countries are exaggerating tensions in the South China Sea region, which is in reality to create confusion and meddle in the South China Sea. China is resolutely opposed to this.”

China’s Defence Ministry said certain countries were conducting “a big show of force” in the South China Sea.

“At the same time, (they are) wantonly expressing remarks to create tensions, in an attempt to sow confusion and muddy the waters,” the ministry said in a faxed statement to Reuters.

China claims most of the South China Sea, through which more than $5 trillion of world trade ships every year, a fifth of it heading to and from U.S. ports.

Beijing is building seven man-made islands on reefs in the Spratly Islands, including a 3,000-metre-long (10,000-foot) airstrip on one of the sites, according to satellite imagery of the area.

Commander of the U.S. Pacific Fleet Admiral Scott Swift sits in front of a large poster of an Australian Navy frigate as he listens to a question during a media conference at the 2015 Pacific International Maratime Exposition in Sydney, Australia, October 6, 2015. REUTERS/David Gray

“Even now, ships and aircraft operating nearby these features, in accordance with international law are subject to superfluous warnings that threaten routine commercial and military operations,” Swift said, speaking at the Cooperative Strategy Forum to naval commanders from Japan, the Philippines, Indonesia and other countries.

A Chinese naval fleet is currently visiting Hawaii, including a destroyer and a frigate, according to China’s Defence Ministry.

Vietnam, Malaysia, Brunei, the Philippines and Taiwan also claim parts of the South China Sea.

AUSTRALIAN PATROL

In October, the U.S. guided missile destroyer Lassen sailed close to one of China’s man-made islands, drawing an angry rebuke from China and a shadowing patrol.

But the U.S. Navy is unlikely to carry out another patrol within 12 nautical miles of Chinese-built islands in the South China Sea this year as officials had initially suggested, U.S. defence officials say.

Australia’s Defence Department said one of its aircraft was involved in “a routine maritime patrol” over the South China Sea from Nov. 25 to Dec. 4. The BBC reported the aircraft was “exercising international freedom of navigation rights”.

“There is no problem with freedom of navigation and overflight in the South China Sea,” Hong said when asked about the Australian patrol.

“Countries outside the region should respect other country’s sovereignty and not deliberately complicate the issue.”

China has been building up its civilian infrastructure in the South China Sea, and over the weekend, opened its first school there, on Woody Island in the Paracels, state media said.

In a challenge to China’s island building program, Manila has asked the Permanent Court of Arbitration in The Hague to affirm its right to areas within 200 nautical miles of its coastline, under the terms of a U.N. convention.

“The Arbitration Tribunal’s case between the Philippines and China could become the latest opportunity to demonstrate lawful access to regional prosperity for all nations,” Swift said.

Beijing so far has rejected the court’s jurisdiction and has boycotted the hearing. Rulings are supposed to be binding on member countries, which include China. But the tribunal has no powers of enforcement and its verdicts have sometimes been ignored.

The People’s Daily, the official newspaper of China’s ruling Communist Party, on Tuesday described the arbitration case as a “farce” designed to rip territory from China it has had sovereignty over since ancient times.