More than 25,000 people have been displaced in the recent fighting, which has been the fiercest in Yemen's key port since a UN-brokered truce in December 2018.
Fighting between troops loyal to Yemen's internationally recognised government and Iranian-backed Houthi rebels has displaced over 25,000 people around a key port city last month.
Clashes have increased elsewhere in recent weeks, such as around the oil-rich city of Marib, United Nations Office for the Coordination of Humanitarian Affairs (OCHA) said late on Tuesday.
It said over 64,450 people have been displaced there since January.
The fighting in Hudaida flared up when rebels rushed into areas abandoned by government forces, followed by a counterstrike by pro-government troops, OCHA said.
Roughly three-fifths of civilians fled to government-held territory, with the remainder heading to the rebels.
The recent fighting in Hudaida has been the fiercest there since a UN-brokered truce in December 2018, although even that agreement was never fully implemented.
Hudaida handles about 70 percent of the country’s commercial and humanitarian imports.
The Saudi-led coalition has also accelerated its airstrikes on Houthi positions in Sanaa as well as the provinces of Marib, Jawf and Hudaida.
The rebels have also fired missiles and explosive-laden drones into Saudi Arabia.
Years of conflict
The conflict in Yemen began in 2014 when the Houthis took over the capital, Sanaa.
A Saudi-led coalition entered the war the following year to try restore the government.
The deadlocked war in Yemen has spawned the world’s worst humanitarian crisis, leaving millions suffering from food and medical shortages.
It has killed over 130,000 people, including fighters and civilians, according to a database project that tracks violence.