'Military options on the table' for North Korea

Malcolm Turnbull says "military options must remain on the table" as the region looks for ways to rein in North Korea.

The threat was at the centre of talks the prime minister had in Tokyo today with Japanese counterpart Shinzo Abe.

The one-time enemies, now allies, highlighted growing defence ties when the two leaders toured a military base, outside Tokyo.

Mr Turnbull agrees with US Secretary of the State Rex Tillerson that military action should not be ruled out.

"The goal is the denuclearisation of the Korean Peninsula that is manifestly in the interests of everyone in the region," Mr Turnbull told the media after touring the base.

And, the prime minister warned the world not to be "glassy eyed" about the decision for the North and South to march under one flag at this year's Winter Olympics, in South Korea.

Mr Turnbull ended his day-long visit with formal talks with Mr Abe, a meeting with the Japanese National Security Council, and dinner at the prime minister's offices.

A re-worked Trans-Pacific Free Trade Agreement, was also on the agenda.

Mr Turnbull returns to Australia in the morning.