Northern Territory Police are requesting public assistance in identifying three alleged offenders who have stolen at least two vehicles this afternoon.

Duty Superintendent Brendan Muldoon said the three persons of interest were last seen heading south on the Stuart Highway, 120 kilometres north of Alice Springs, around 5:00pm.

"Members were called to Aileron Roadhouse where they were informed the three offenders had threatened tourists with a knife before assaulting one of them and stealing a silver Holden Rodeo utility, Queensland registration 647 VPV.

"Police are asking anyone who sights this vehicle or who can identify the offenders to call police as soon as possible on 131 444.

"Any occupants of the vehicle should not be approached."