The toll comes as gang violence in Port-au-Prince this week left 30 residents dead and more than a dozen injured.
"Between January 1 and August 15 of this year, at least 2,439 people have been killed and a further 902 injured," UN rights office spokeswoman Ravina Shamdasani told reporters in Geneva.
In addition, she said, "951 people have been kidnapped" during the same period.
And as anger grows over the gang violence, she warned that a rise in popular justice movements and self-defense groups was spurring further violence.
"Since April 24 up to mid-August, more than 350 people have been lynched by local people and vigilante groups," she said, adding that of those, 310 were alleged gang members and one was a police officer.
"Reports from Haiti this week have underscored the extreme brutality of the violence being inflicted on the population and the impact that it is having on their human rights," Shamdasani said.