The UN envoy for Yemen arrived in the rebel-held capital Sanaa on Saturday for talks on the key aid port of Hodeida where rebel fighters are battling a regional coalition.
Martin Griffiths is expected to propose to rebel leaders that they cede control of the Red Sea port to a UN-supervised committee to avoid further fighting with advancing government troops which are backed by Saudi Arabia and the United Arab Emirates.
He did not speak to reporters upon arriving at Sanaa international airport.
More than 70 percent of Yemeni imports pass through Hodeida's docks and the fighting has raised UN fears of humanitarian catastrophe in a country already teetering on the brink of famine.
The Yemeni government and it allies launched their offensive on Wednesday. Ar least 139 combatants have already been killed, according to medical and military sources.
The rebels have controlled the Hodeida region with its population of some 600,000 people since 2014.
Earlier this year, the Saudi-led coalition imposed a near-total blockade on the city's port alleging that it was being used as a conduit for arms smuggling to the rebels by its regional arch rival Iran.
The capture of Hodeida would be the coalition's biggest victory of the war so far and on Thursday rebel leader Abdel Malek Al-Huthi called on his forces to put up fierce resistance and turn the region into a quagmire for coalition troops.