Scammers are using the broadband brand NBN to trick customers out of more than $110,000 a month.
The Australian Competition and Consumer Commission says losses from January to May this year were almost triple that over the whole of last year.
"People aged over 65 are particularly vulnerable, making the most reports and losing more than $330,000 this year," ACCC acting chair Delia Rickard said on Monday.
"That's more than 60 per cent of the current losses."
Among the types of scam are:
* someone pretending to be from NBN Co or an internet provider calls a victim and claims there is a problem with their phone or internet connection, which requires remote access to fix. The scammer can then install malware or steal valuable personal information, including banking details.
* scammers pretending to be the NBN attempting to sell NBN services, often at a discount, or equipment to you over the phone.
* scammers may also call or visit people at their homes to sign them up to the NBN, get them a better deal or test the speed of their connection, asking for personal details such as their name, address, date of birth, and Medicare number or requesting payment through gift cards.
NBN Co is a wholesale-only company and does not sell its services directly to consumers.
"We will never make unsolicited calls or doorknock to sell broadband services to the public. People need to contact their preferred phone and internet service provider to make the switch," NBN Co chief security officer Darren Kane said.
"We will never request remote access to a resident's computer and we will never make unsolicited requests for payment or financial information."
Australian Associated Press