Northern Territory Police have responded to a serious crash in East Arnhem Land overnight.

At around 9:30pm, police received reports that an SUV carrying two males had collided with a road train.

Emergency services attended and the scene and the two occupants of the SUV were conveyed to the local clinic in a serious condition.

One man has since been transferred to Royal Darwin Hospital, while the other has been transferred to Gove District Hospital.

The driver of the road train returned a negative road-side breath test.

Police are currently investigating the cause of the crash.