IAEA chief Rafael Grossi said Iran had informed the Vienna-based UN nuclear agency that from February 23, Tehran was planning to "stop implementing voluntary transparency measures" that form part of the hard-won international agreement.

"Director General Grossi has offered to travel to Iran in order to find a mutually agreeable solution for the Agency to continue essential verification work," the IAEA said, after member states were given a report on the situation Tuesday.

The landmark nuclear deal, aimed at limiting Tehran's nuclear programme in exchange for international sanctions relief, is hanging by a thread.

Former US president Donald Trump withdrew from the accord in 2018 and reimposed sanctions on Tehran, with Iran a year later gradually suspending its compliance with most key nuclear commitments in response.

Under the agreement, known as the Joint Comprehensive Agreement Plan of Action (JCPOA), IAEA inspectors are supposed to have limited access to non-nuclear Iranian facilities, including military sites, in cases of suspected illegal nuclear activity.

But under a law passed by Iran's parliament in December, Iran is set to stop allowing the intrusive inspections in late February unless there is an easing of US sanctions.

Trump's successor Joe Biden has said the US intends to return to the deal, but that Washington will only return to full compliance once Iran does.

The IAEA said in its statement that Grossi was "continuing to consult with Iran", without giving further details on plans for any visit.

Grossi has only been to Iran once since taking over the helm of the IAEA in 2019.

But the visit in August 2020 was considered a success, leading to IAEA inspectors eventually winning access to two sites where undeclared nuclear activities may have taken place in the early 2000s.

Iran on Monday reiterated that opposition to nuclear weapons was its official policy.