Iran on Friday denied US accusations it has delivered missiles to Yemeni rebels, retorting it was US support for a Saudi-led coalition backing the government that had prolonged the conflict.

Foreign Minister Mohammad Javad Zarif said the comments by Secretary of State John Kerry on a visit to Saudi Arabia on Thursday were "completely baseless".

"Iran has repeatedly said that Iranian military power will never be a threat to any country and is merely for defence purposes," Zarif said in a statement on the ministry's website.

"The US administration with such remarks is itself becoming a partner in the child killings and war crimes committed by the Saudi regime against the innocent people of Yemen.

"Undoubtedly, Mr Kerry knows better than others that the Saudi government in the past year and half has consistently and seriously blocked all efforts made to establish a ceasefire in Yemen."

The Saudi-led coalition intervened in Yemen in March last year after the rebels and their allies overran most of the country, prompting President Abedrabbo Mansour Hadi to flee into exile.

The UN brokered three months of peace talks in Kuwait but they were suspended earlier this month when the government reacted angrily to the rebels' appointment of a new ruling council in Sanaa.

Kerry announced a fresh peace initiative on Thursday aimed at forming a unity government but hit out at Iran for what he said was its support for the Shiite rebels.

"The threat potentially posed by the shipment of missiles and other sophisticated weapons into Yemen from Iran extends well beyond Yemen and is not a threat just to Saudi Arabia and... the region," he told reporters.