Those escaping the violence, which resumed in August, are seeking shelter in camps and with host families in the southern provinces of Hajjah and Amran, the U.N. High Commissioner for Refugees said Friday.
"This new displacement puts increasing pressure on UNHCR's attempts to alleviate the suffering of the people in need," UNHCR spokesman Andrej Mahecic said.
Almost 175,000 people have been uprooted by the violence in Yemen since 2004, including the refugees from the most recent upsurge, the UNHCR estimates.
One camp in Hajjah has exceeded its capacity with nearly 10,000 displaced persons, the U.N. says.
"The latest sudden influx is adding more pressure on an already dire situation, and overcrowding in the camp is becoming a major concern," Mahecic said.