The British Infrastructure Group (BIG) has criticised broadband providers for failing to tell customers when introductory rates end.
According to research by First Utility, 15 million homes in the UK pay an average of £113 a year more for their broadband due to teaser rates expiring.
As a result, consumers are collectively paying £1.7 billion in "out-of-contract" fees.
First Utility believes this is largely because broadband providers don't tell customers when their initial contract price ends and their monthly payments go up.
Responding to the findings, the BIG said it is "outrageous" that so many people are paying more than they have to for broadband.
Grant Shapps MP, Chair of the cross-party body, commented: "Providers should be more transparent about their pricing changes and not prey on customer apathy.
"Other industries have cottoned on to the fact that consumer reminders help to drive engagement, and it’s time the broadband industry followed suit."
Entrepreneur, consumer champion and former star of the BBC's Dragons' Den Sarah Willingham joined the chorus of criticism, saying it is "appalling" that millions of families are being "ripped off by their broadband supplier".
"We have already learnt that loyalty doesn’t pay in energy and it’s shocking to see the same thing happening in broadband," she said.
Willingham went on to argue that the big providers have been "let off easily for far too long", adding that it "shouldn't be too much effort" for providers to remind customers when their contract is coming to an end.
Ed Kamm, Head of Commercial at First Utility, this week stated that broadband is "lagging behind many sectors and proving to be among the worst industries for customer communication".
"It’s about time it caught up and formalised the process of communicating out-of-contract plans with customers," Mr Kamm stated.