People are being urged to be aware of scammers attempting to con people out of their money by posing as striking ambulance staff.
The first national ambulance strike in 30 years is planned for next Wednesday, with 10,000 ambulance workers due to join walkouts.
In a statement posted to social media, the North West Ambulance Service (NWAS) said the fraudsters are pretending to be ambulance service staff asking people for donations to cover wages lost due to strike action.