Yemen's Huthi rebels have blamed the Saudi-led coalition for the attack on the wedding in northern Hajjah province late Sunday.

Guterres "strongly condemns the airstrikes on a wedding party in Hajjah and on civilian vehicles in Taez, where at least 50 civilians, including children, were reportedly killed and scores of others injured," said a UN statement.

The UN chief "reminds all parties of their obligations under international humanitarian law concerning the protection of civilians and civilian infrastructure during armed conflicts."

He called for "a prompt, effective and transparent investigation" of the air strikes which were carried out as the United Nations is seeking to re-launch political talks to end the war in Yemen.

Guterres last year put the Saudi-led coalition on a UN blacklist of child rights' violators for killing and maiming children in Yemen.

The coalition intervened in March 2015 to push back the Huthis who continue to control the capital Sanaa.

The Huthis on Monday accused the coalition of killing their political leader, Saleh al-Sammad, in an air strike last week.

The war in Yemen has killed thousands of people and led to the world's worst humanitarian crisis, with 75 percent of the population in dire need of aid while one million Yemenis have been ill from cholera.