Man dead after car hits livestock in NT

A man is dead and three people injured after their car struck livestock on a highway in the Northern Territory.

Police say the Holden Astra they were travelling in hit the livestock on the Barkley Highway early on Saturday and veered off the road into scrubland.

A 35-year-old front seat passenger died at the scene, while the male driver was airlifted to Alice Springs Hospital in critical condition.

Two female passengers were taken to Tennant Creek Hospital for treatment on minor head injuries.

The death takes the territory's annual road toll to 21.

NT Police also said a 17-year-old girl died after she was struck by a vehicle in Epenarra on Friday.

The teenager died about 2.30pm on a private property, which means the death isn't counted in the road toll.

An 18-year-old woman is assisting police with investigations into the incident.