Detectives investigating the death of a New Zealand firefighter in New South Wales' Hunter region two years ago are appealing for an anonymous caller to come forward

Ian Pullen's body was found on the side of the road in Glenridding just after 5.30am in September 2018.

The 43-year-old had gone to the region to help with bushfire efforts and investigators believe he was hit by a vehicle earlier in the morning.

An anonymous caller told police the vehicle involved returned to the scene and the occupants got out and checked on Pullen, who at that stage was still alive.

There's an 350-thousand Australian dollar reward on offer for information that leads to the arrest and conviction of those responsible for Mr Pullen's death.