More than 10,000 people have fled their homes in parts of Haiti's central department, the United Nations' migration agency said on Wednesday, after a series of gang attacks in recent days including in a hospital north of the capital.

Under-resourced police have struggled with heavily armed gangs who gained territory and massively expanded their influence over the past year, forming powerful alliances notably in the capital Port-au-Prince.

Fighting has expanded in recent months, spiking in regions such as Artibonite and the Central Department.

Early on Tuesday, armed men attacked the University Hospital of Mirebalais, one of the country's main health centres. Days earlier, suspected gang members attacked a police station in nearby Saut-d'Eau.

Haiti's top private healthcare provider Zanmi Lasante issued a statement shared by local media condemning the "brutal attack which violates the moral treaty which considers hospitals as neutral sites, leaving patients and medical personnel deeply traumatized."

No people were immediately reported killed or injured in the attack, but unverified videos on social media showed chaotic scenes with broken windows and hospital walls riddled with bullet holes.

Violence has spiked since last week, when the leader of the powerful G9 gang alliance Jimmy "Barbecue" Cherizier said he would overthrow the government by force and called a broader truce of metropolitan area gangs through a new alliance called "Living Together."