NT Police is investigating two fatal crashes in central Australia, with one man killed in a rollover near Hermannsburg on Saturday, and a man killed on a quad bike on the Finke track on Friday.

Police media manager Margaret McKeown said in a statement police were investigating a single vehicle rollover that happened at an undefined time early Saturday morning on Larapinta Drive, 6.5kms east of Hermannsburg.

She said a man, whose age was not given, was declared dead at the scene while three men suffered various levels of injuries and all were taken Alice Springs Hospital for assessment, with one man in a serious condition.

Ms McKeown said the Major Crash Investigation Unit were investigating the fatal motorbike crash near Alice Springs yesterday.

About 4pm, she said, emergency services were notified of a collision between a motorbike and quad bike on the Finke track near Maryvale Rd, 35km south of the Stuart Hwy intersection.

She said the 27-year-old man who was riding the quad bike was declared dead at the scene, while a 24-year-old man who was riding the other motorcycle was taken to Alice Springs Hospital in a serious condition, and has since been flown interstate for treatment.