AFP - Iran on Monday rejected a US court order for Tehran to pay $180 million in damages to a Washington Post reporter for jailing him on espionage charges.

Jason Rezaian spent 544 days in an Iranian prison before he was released in January 2016 in exchange for seven Iranians held in the United States.

On Friday, a US district court judge ordered damages be paid to Rezaian and his family in compensation for pain and suffering as well as economic losses.

The Iranian foreign ministry's spokesman described the journalist's decision to seek damages as "strange".

"Mr Jason Rezaian... was a security convict and the Islamic Republic of Iran commuted his (sentence of maximum punishment) to imprisonment," said spokesman Abbas Mousavi.

"He was pardoned and despite having an open case... he was released," Mousavi told a news conference in Tehran.

"For him to go there and lodge a complaint and for American courts to lavishly determine such figures" was a course of action that Iran "rejects", said Mousavi.

"This was a favour that the Islamic Republic of Iran did for him," he said, adding that he could have been kept behind bars and punished more severely.

Mousavi said Iran could itself take similar legal action against the United States, without elaborating.

Relations between arch-foes Tehran and Washington plunged to a new low in May last year when the US withdrew from an international accord that gave Iran relief from sanctions in return for curbs on its nuclear programme.

Rezaian and three other Americans were released on January 16, 2016, the day the nuclear agreement entered into force.