Japan dispatched its biggest warship since World War II to protect a US supply ship, as tensions mount in the region over North Korea. Picture: AFP.

The helicopter destroyer Izumo departed from the Yokosuka port near Tokyo on Monday morning.

The destroyer was to meet up and escort a US supply ship in the Pacific Ocean south of Tokyo later on Monday, a new mission under the new security legislation allowing Japan’s military a greater role in overseas activity, according to Japanese media reports.

They said that the US supply ship is expected to refuel other American warships, including the USS Carl Vinson strike group, currently in the region.

Japan's Maritime Self Defence Forces helicopter destroyer Izumo sails out its Yokosuka Base in Kanagawa prefecture. Picture: AFPSource:AFP

Japan’s defence ministry only said that the Izumo left on Monday to eventually participate in an international naval event in Singapore on May 15.

Tensions have increased as North Korea pushes to develop its missile and nuclear weapons programs in defiance of international sanctions and President Donald Trump warns of the potential threat Pyongyang’s action pose to other countries.

Mr Trump sent the USS Carl Vinson toward the region, and the US and South Korea also started installing a missile defence system that is supposed to be partially operational within days.

Prime Minister Malcolm Turnbull used a commemoration of a World War II naval battle to warn North Korea against military threat.

“Today Australia and the United States continue to work with our allies to address new security threats around the world,” Mr Turnbull said.

“Together, we’re taking a strong message to North Korea that we will not tolerate reckless, dangerous threats to the peace and stability of our region.”

Mr Turnbull will meet Mr Trump for the first time on Thursday in New York.

Prime Minister Malcolm Turnbull lays a wreath at the 75th anniversary commemoration of the battle of the Coral Sea in Townsville. Picture: AAP Image/Andrew RankinSource:AAP