Tehran on Tuesday played down a decision by the United States to boycott meetings of the UN Conference on Disarmament when Iran takes over the body later this month.

"Pressure, presence or their boycott will not be important to Iran," newly appointed foreign ministry spokesman Abbas Araqchi told reporters when asked about the planned boycott by US ambassadors when Iran takes over.

Iran will take over presidency of the disarmament conference from May 27 until June 23 under an alphabetical rotation among the 65 member states.

The conference is struggling to craft a deal on nuclear disarmament, preventing arms from spreading to outer space and halting the development of other weapons of mass destruction.

"Iran has had a very active presence in the conference and its initiatives," Araqchi said. "We will continue this role, whether it is in a participation capacity or presidency" of the conference.

The boycott was announced in Washington on Monday by Erin Pelton, spokeswoman for the US mission at the United Nations.

"The United States continues to believe that countries that are under Chapter VII sanctions for weapons proliferation or massive human-rights abuses should be barred from any formal or ceremonial positions in UN bodies," she said.

"The United States will not be represented at the ambassadorial level during any meeting presided over by Iran," she added.

Iran meanwhile faces four rounds of UN sanctions over its nuclear programme.

The International Atomic Energy Agency is responsible for investigating Iran's nuclear programme, which western nations say hides a bid to develop a nuclear weapon. Iran denies the charge.

The conference was launched in 1979 to try to stem the Cold War arms race.

Iran takes over the conference presidency from Indonesia and at the end of June hands over to Iraq.