Police have had numerous reports of the hoax calls over recent weeks.
The scammers contact the victim, saying they need to speak to them about issues with their Spark account or computer.
In the Tasman area alone, three elderly residents have been conned out of a total of $120,000.
Early investigations show the funds have been sent into Australian bank accounts.
Spark's General Manager of Care Bridgette Dalzell said Spark would never call customers out of the blue to ask for personal details such as bank account number, credit card, or internet banking details.
``If you receive a call from someone claiming to be from Spark who asks for your personal information, end the call immediately.''
A police spokesperson said anyone who calls and asks for financial information shouldn't be trusted.
Police advise anyone who gets such a call to hang up, call the company on their published 0800 number, or arrange a meeting at the relevant agency branch.
Anyone who believes they've been targeted by the scam should report it to the Consumer Protection Scamwatch website, at www.consumerprotection.govt.nz/get-guidance/scams-and-online-safety/scams.
