US President Donald Trump has designated North Korea a state sponsor of terrorism as part of the United States’ “maximum pressure campaign” against Pyongyang’s nuclear program.

The designation, announced by Mr Trump on Tuesday morning (AEST), allows the US to impose additional sanctions and penalties against North Korea.

The President, who has traded personal barbs and insults with North Korean leader Kim Jong-un, said the Treasury Department will announce the additional sanctions against North Korea on Tuesday local time.

The designation came a week after Mr Trump returned from a 12-day, five-nation trip to Asia in which he made containing North Korea’s nuclear ambitions a centrepiece of his discussions with world leaders.

“Today, the United States is designating North Korea as a state sponsor of terrorism,” Mr Trump said at the White House.

“Should have happened a long time ago, should have happened years ago.”

Mr Trump said that North Korea had “repeatedly supported international acts of terrorism” and that the regime must act lawfully and also cease its nuclear weapons program.

Prime Minister Malcolm Turnbull strongly endorsed the move, saying Mr Trumps decision mirrored an international commitment to bring the rogue state to its senses.

“Kim Jong Un runs a global criminal operation from North Korea pedalling arms, pedalling drugs, engaged in cyber-crime and of course threatening the stability of region with his nuclear weapons,” Mr Turnbull told reporters in Sydney.

North Korea is pursuing nuclear weapons and missile programs in defiance of UN Security Council sanctions and has made no secret of its plans to develop a missile capable of hitting the US mainland. It has fired two missiles over Japan.

South Korea’s spy agency said on Monday said North Korea may conduct additional missile tests this year to polish up its long-range missile technology and ramp up the threat against the US.

“This designation will impose further sanctions and penalties on North Korea … and supports our maximum pressure campaign to isolate the murderous regime,” Mr Trump said.

The President said new sanctions announced over the coming weeks, including Tuesday local time by the Treasury Department, will bring US sanctions against Pyongyang to their highest level ever.

The US proposed a range of United Nations sanctions against North Korea in September in response to Pyongyang’s sixth nuclear test and repeated missile launches.

North Korea joins Iran, Sudan and Syria on a list of countries the US has deemed to have repeatedly provided support for acts of international terrorism.

North Korea has been on the list before but was removed in 2008 by the administration of George W Bush as part of negotiations on the North’s nuclear program.

– With agencies