Iran's ultraconservative President Ebrahim Raisi plans to travel to New York for the UN General Assembly next month despite US sanctions against him, the government's spokesman said on Tuesday.

"The preliminary planning has been done for the president's attendance at the UN General Assembly session," Ali Bahadori-Jahromi told a weekly press briefing.

Raisi, who has been under US sanctions since November 2019 for "complicity in serious human rights violations", missed last year's General Assembly because of the Covid-19 pandemic. A pre-recorded video of his address was played to the meeting instead.

When Washington added his name to its blacklist of Iranian officials, Raisi was still judiciary chief. He became president in June 2021.

Washington accuses him of playing a leading role in mass executions of detained leftists in 1988 while he was chief prosecutor of the Tehran revolutionary court.

Raisi has denied the allegations on two occasions -- in 2018 and 2020 -- insisting he played no role in the executions, although he lauded an order he said was handed down by the Islamic republic's founder Ayatollah Ruhollah Khomeini to proceed with the purge.

The General Assembly opens in New York on September 13.