The Saudi-led coalition carried out a deadly "double-tap" air strike on a funeral ceremony in Yemen this month in violation of its obligations under international humanitarian law, a UN panel of experts concluded.

The experts told the UN Security Council in a report obtained by AFP on Thursday that it continues to investigate whether the second air strike directly harmed medical personnel in what could amount to war crimes.

More than 140 people were killed and 525 injured in the air strike on October 8 on a community hall packed with 750 mourners attending the funeral of the rebel Huthi interior minister's father.

"The panel has not seen any demonstrable evidence to suggest that the Saudi Arabia-led coalition took effective and adequate precautionary measures to minimize civilian casualties in respect of the two air strikes so far confirmed," said the report sent to the council on Monday.

"In contrast, there is evidence to suggest that the Saudi Arabia-led coalition violated its obligations relating to the protection of the wounded and persons hors de combat in its second air strike."

Those killed in the bombing included the head of the Huthi Republican Guard, the mayor of Sanaa, a prominent member of the Huthi military council, two commanders and a former governor.

Yemen's former president Ali Abdullah Saleh and his son attended the funeral, but left before the attack, the report said.

The experts found that the timing between the two strikes indicated the "deliberate use of the 'double tap' tactic, the consequences of which are that individuals responding to the first explosion are caught by the second."

The attack resulted in "disproportionately higher numbers of civilian casualties, when compared to military casualties, and that this could have been anticipated prior to the attack," the report added.

The Saudi-led Arab coalition announced a ceasefire after the attack on the funeral ceremony triggered global outrage and prompted the United States to review its support of the air war in Yemen.

The coalition intervened in March 2015 to support the government of President Abedrabbo Mansour Hadi after Huthi rebels overran much of the impoverished country.

Nearly 6,900 people have been killed -- more than half of them civilians -- in the conflict, while another three million are displaced and some 70 percent of the population needs food aid.

The panel said it was waiting for a response from the coalition's head of investigation concerning its findings.