Iran on Tuesday denied a South Korean report that its missile experts were in North Korea offering technical assistance for the planned launch of a long-range rocket.

"This issue is utterly not true," Ramin Mehmanparast, foreign ministry spokesman told reporters.

"The claim made regarding missile and nuclear cooperation is baseless propaganda and they are trying to create fear so they can undermine our relations with others," he added.

Mehmanparast said that during the Iran-Iraq war in the 1980s "there was military cooperation, but after the war we continued our political, economic and humanitarian ties and still have them in these fields."

On Monday, Chosun Ilbo newspaper said a group of Iranian missile experts was in North Korea offering technical assistance for the planned launch of a rocket which Pyongyang terms a peaceful mission aimed at putting a satellite in orbit.

The Iranians were invited after North Korea's last rocket launch in April ended in failure, the newspaper said, citing a Seoul government official.

Earlier this month, Japan's Kyodo news agency quoted a Western diplomatic source as saying Iran had stationed defence personnel in North Korea since October to strengthen cooperation in missile and nuclear development.

North Korea and Iran are both subject to international sanctions over their nuclear activities and their governments share a deep hostility towards the United States.

Leaked US diplomatic cables in 2010 showed that US officials believe Iran has acquired ballistic missile parts from North Korea. A 2011 UN sanctions report said the two countries were suspected of sharing ballistic missile technology.