Warning issued over stolen NSW safe

A safe full of rifles stolen from a NSW property could be more trouble than it's worth due to a dangerous substance inside, police have warned.

Officers issued the warning after the safe was stolen sometime between Monday night and Tuesday morning from a residence on Orange Street, Parkes, saying it contained not only five rifles and a shotgun but also gunpowder.

If forced open, the contents of the safe could cause significant injury, police say.

"Gunpowder is explosive obviously near an open flame ... if they tried to weld open the safe it would be dangerous," a NSW police spokesman told AAP on Wednesday.