Better Sino-US ties needed given rising risk of military clash, Chuck Hagel says

US defence chief Chuck Hagel warned that communication was needed more than ever amid the heightened risk of a clash between China and the United States as the world's two largest militaries seek to bolster their presence in the Asia-Pacific region.

Hagel told officers and students at China's National Defence University that the US "pivot to Asia" and the People's Liberation Army's modernisation would draw the two sides into "closer proximity", increasing "risks of an incident, an accident or a miscalculation" unless they step up communication.

"The Asia-Pacific region is the most militarised in the world and any one of these challenges could lead to a conflict, a deadly conflict," Hagel said.

"The cost of conflict will rise as economic interdependence grows."

He called on the two militaries to establish a new relationship that stressed co-operation and dialogue.

"It seeks to manage competition, but avoid the traps of rivalry," he said. "We must do our part to build greater trust, confidence and co-operation between our two militaries."

Hagel cited the role of communication during the "near- catastrophe" at sea when the guided-missile cruiser USS Cowpens almost collided with a Chinese navy ship attached to vessels escorting the aircraft carrier Liaoning in December.