N Korea is top issue for 2017: Rudd

North Korea has enough nuclear material to make bombs, and the issue should be one of the most concerning for the world in 2017, former prime minister Kevin Rudd says.

Mr Rudd told an Asia Society forum in New York on Wednesday night (NYC time) the Iranian nuclear program was "just a baby" compared with that of North Korea.

He said North Korea's program was moving at such a pace "it is crossing one technical threshold after another, now constituting real threats in terms of its immediate neighbours and prospectively having a larger and wider radius from Pyongyang".

Mr Rudd, who is now president of the Asia Society, said North Korea had "mastered" short and medium range rockets and it was now a question of whether it can develop intercontinental ballistic missiles.

"Do they have enough nuclear material to constitute nuclear bombs - yes they do, about 15 at present depending on how it is measured," Mr Rudd said.

"This is a real live national security challenge for the United States and its allies and other countries across the region - it's the biggie for 2017."

In his New Year's speech, leader Kim Jong Un said North Korea was close to test launching an ICBM, and state media has said a launch could come at any time.

The Trump administration intends to develop a "state of the art" missile defence system to protect against attacks from Iran and North Korea.