Emergency services were called to a stretch of the highway just east of Hay about 5.30pm on Monday, January 15, following reports of collision involving a B-double and a car.

A NSW Police spokesperson said initial reports suggested two people have died in the crash and another person has sustained critical injuries.

The injured person is expected to be flown from Hay for further treatment.

Flight radar mapping shows an Ambulance Victoria rescue helicopter was sent to Hay from Bendigo shortly after the crash and has since landed at the town's hospital.

No further details were available at 7pm.

Multiple emergency service personnel are at the crash scene, including police, paramedics, Fire and Rescue NSW firefighters and NSW State Emergency Service and NSW Rural Fire Service volunteers.

Initial information suggests the truck was carrying fruit and rolled following the impact.

The crash, which happened near near Old Common Road, has closed the Sturt Highway in both directions.

Eastbound motorists are being diverted into the Cobb Highway through the Hay township, then onto the Mid Western Highway, Murrumbidgee River Road and Carrathool Road.

The diversion is the same in reverse for westbound travellers.

The NSW Transport Management Centre said the diversion was suitable for all vehicles but motorists should allow extra travel time.

It is understood the highway will be closed for some time, with crash investigators headed to the scene.