Iran's intelligence minister on Wednesday defended a nuclear negotiator imprisoned on spying charges in a rare implied criticism of the judiciary.

Abdolrasoul Dorri Esfahani, a Canadian-Iranian, was given a five-year prison sentence this month, with the judiciary saying he had provided "information for foreigners and had links with two espionage services".

But the charges were dismissed by Intelligence Minister Mahmoud Alavi in comments carried by multiple Iranian news agencies, including the semi-official ISNA.

"The counter-espionage section of the Intelligence Ministry is the authority detecting issues related to espionage," said Alavi.

"As far as this section is concerned, not only has Dorri Esfahani not committed any espionage, but he has intelligently resisted attacks on him by foreign services."

The intelligence ministry comes under the office of President Hassan Rouhani, which led the negotiations with world powers that resulted in the 2015 agreement.

The judiciary is independent and dominated by conservatives.

It has been regularly criticised abroad for its actions, particularly over the imprisonment of dual nationals and foreigners, but rarely by other branches of the Iranian government.

"The ministry of intelligence was responsible for protecting and safeguarding the nuclear negotiations, and has carried out one of its most outstanding activities in this field," said Alavi.

Dorri Esfahani has a background in the banking sector and was a member of the supervisory board overseeing implementation of the nuclear deal.

From mid-2016, conservative websites and members of parliament repeatedly accused Dorri Esfahani of spying for Britain.

Alavi flatly denied the accusations in October 2016, but the judiciary went ahead with the case.

source: AFP