Northern Territory Police is investigating a "non-suspicious" road fatality on the Victoria Highway, about 200 kilometres south-west of Katherine.
At about 5:15pm on Thursday, police received a report of "a man trapped underneath a trailer" about 10km east of the Victoria River Roadhouse.
NT Police said officers went to the scene where the man was declared deceased.
St John Ambulance NT operations manager Craig Garraway said medical staff from Timber Creek Health Centre also attended the scene.
"They were unable to help the gentleman involved in that and he passed away on the scene," Mr Garraway told ABC Radio Darwin this morning.
"So it's very sad for the drivers involved in that incident."
NT Police said the Katherine Criminal Investigation Branch was investigating the circumstances of how the driver became trapped underneath the trailer.
NT Worksafe has been notified.
The truck and trailer remain blocking the inbound lane to Katherine on the Victoria Highway and motorists are being urged to avoid the area.
NT Police has encouraged any witnesses to come forward, particularly those with dashcam footage, who may have seen a truck and trailer pulled over on the Victoria Highway, near the Victoria River Roadhouse.
A report will be prepared for the coroner.
