The warring sides in Yemen's seven-year conflict have for the first time in years agreed a two month nationwide truce.

The halt to hostilities would also allow fuel imports into Houthi-held areas and some flights operating from Sanaa airport, the UN envoy said on Friday.

The UN-brokered deal between a Saudi-led coalition and the Houthi group backed by Iran is the most significant step yet towards ending a conflict that has killed tens of thousands and pushed millions into hunger.

UN special envoy Hans Grundberg said the truce would come into effect on Saturday at 7 p local time (1600 GMT) and could be renewed with consent of the parties. Saturday marks the start of the Muslim holy month of Ramadan.

"The aim of this Truce is to give Yemenis a necessary break from violence, relief from the humanitarian suffering and most importantly hope that an end to this conflict is possible," Grundberg said in a statement, adding he would press for a permanent ceasefire.

Yemen's economy and basic services including health have collapsed, leaving 80% of the population of around 30 million reliant on aid.

UN Secretary-General Antonio Guterres said the truce "must be a first step to ending Yemen’s devastating war", urging the parties to build on the opportunity to "resume an inclusive and comprehensive Yemeni political process".

Houthi rebels launched a fierce drone and missile attack last week on Saudi oil installations, as behind the scenes talks were most probably taking place.