Lake Illawarra police have urged residents to be cautious of phone fraudsters calling landlines and claiming to represent Telstra.
The Mercury reported on Friday police were receiving one report of attempted fraud every 24 to 48 hours.
A 50-year-old Cringila man was contacted on Wednesday and provided personal details to a caller claiming to be from Telstra and inquiring about his internet service. The man was contacted by the National Australia Bank about an unauthorised transfer of a significant amount of money to a Western Union account.
Sgt Jason Harrison from Lake Illawarra police said he himself received one of the calls last week, with the caller becoming evasive and then abruptly hanging up after being questioned on their authenticity.
"They open with a quick, crafty line about representing Telstra with new products and ask for personal information," he said.
"It is out there, even if people are not reporting the calls to us."
Lake Illawarra police posted a warning on their Facebook page on Thursday, with at least a dozen people commenting they had received the calls - in some cases, they had been contacted up to four times.
"I got the same call saying they were from Telstra and my internet would be disconnected. They called three times in one night," wrote one commenter.
"I got the same phone call this week … saying they are from Telstra tech support and they were going to disconnect my internet as I downloaded a virus into my computer [and] they wanted me to go through my computer over the phone," wrote another.
Sgt Harrison said anyone suspecting they are being targeted by this scam should never pass on their own details, but instead ask for the caller's name, employee number and a phone number to call them back on.
"You are welcome to report the calls to police, or call Policelink on 131 444 to report an attempted fraud," he said.