Emergency services were called to the scene three kilometres south of Gundagai about 3.40am, and found a southbound B-double had crossed to the wrong side of the highway and crashed down an embankment, partially blocking northbound lanes.

The driver was ejected from the cabin and died at the scene.

A short time later, two B-doubles driving north came across the crashed heavy vehicle; one was able to avoid the wreckage but the second hit the trailer.

While neither driver was injured, the highway is now blocked northbound.

All vehicles were laden with general freight. Officers from the Riverina Police District are conducting investigations.

There may be short closures of all southbound lanes as the salvage and clean-up continue and investigations into the crash are carried out throughout the day.

Northbound motorists are advised to use the Snowy Mountains Highway through to Tumut, then Gocup Road to rejoin the Hume Highway.

The diversion adds approximately 40 minutes of travel time.

All southbound lanes remain open on the highway however traffic is slow so also allow extra travel time and exercise caution past the crash site.