"In one particular case their bank accounts have actually been emptied."
He said the victims were "hit quite aggressively".
People were also being "bombarded, literally hour after hour" with scam callers claiming to be representing various companies.
Mr Nottage stressed Spark employees would not call people and ask for access to their computers.
A post on the Spark Wanganui Facebook page said Spark employees would never ask people to visit a specific website and click on a link or ask for access to their computer.
"These people will hold your computer to ransom or hack your bank account. If in doubt ask the person to hold while you call your local Spark store to verify their identity. Then call us 063482276."