Scammers posing as power company staff are targeting elderly people in Canterbury.
The scammers have taken at least $20,000 from 11 residents in Prebbleton, Mt Pleasant, Murray Hill, Rangiora, Riccarton and Somerfield, Detective Sergeant Jennifer Hooke says.
They have telephoned victims pretending to be from Meridian or another power company, saying payments are not going through and requesting PIN numbers and bank account details.
"After the call has finished another scammer knocks on the victim's door posing as a bank employee to collect the faulty cards and provides them with a replacement card and documentation."
The replacement card is actually a prezzy card, Det Sgt Hooke said.
The scammers appeared plausible, but were pushy, she said.
They appear to be targeting retired people living on their own, in retirement villages or rest homes.
Police are following leads, but want to hear about any similar events.
"Everyone has a right to be safe and feel safe in their homes and this sort of behaviour will not be tolerated."