Scammers posing as staff from Meridian or other power companies have so far netted $20,000 from people in Canterbury, and police warn others to be on the lookout.
The scammers are targeting the elderly including those living in retirement villages or rest homes.
Police have received 11 reports so far from residents in Prebbleton, Mt Pleasant, Murray Hill, Rangiora, Riccarton and Somerfield.
Detective Sergeant Jennifer Hooke said the scheme involved one of the scammers ringing a victim and telling them that their power bill payments were not going through.
They then requested the resident's PIN numbers and bank account details.
Another scammer then knocks on the resident's door posing as a bank employee to collect the so called 'faulty' cards and provides them with false replacement cards and documents, Ms Hooke said.
The cards, account details and PIN numbers were then used to make withdrawals.
"From the information the victims have provided the scammers, at least one man and one woman, appear plausible and knowledgeable but can be pushy."
"No reputable company will ask for your bank details, PIN numbers or other personal information over the phone or visit your home to collect 'faulty' cards. The replacement card is actually a pressie card.
"Police are following a positive line of inquiry into this matter, but urge the public to report any similar events straight away."
