NSW Ambulance contacted the Westpac Rescue Helicopter Service (WRHS) after reports of the 20-year-old's wound emerged.

Muswellbrook paramedics treated the male on the scene before rendezvousing with the WRHS at Victoria Park.

"The helicopter's critical care medical team stabilised the man," a WRHS spokesperson said.

"He was then flown direct to the John Hunter Hospital in Newcastle."