FEARS that consumers would be hit with massive bills after signing up to the national broadband network may prove groundless, with new research finding almost two-thirds of customers pay the same or less than before.

After interviewing 282 households in Brunswick, one of the first neighbourhoods in Australia connected to the NBN, researchers from the University of Melbourne and Swinburne University of Technology found 63 per cent of households that joined the NBN reported their internet bills had either stayed the same or decreased. About 26 per cent said their bills had increased somewhat.

''Some of the reporting or debate around [the NBN] has been the potential for an increase in household costs for internet when people take up the broadband,'' said Bjorn Nansen, a research fellow from the department of computing and information systems at the University of Melbourne. ''From our standpoint, costs do not dramatically increase when you're shifting from other broadband to high-speed broadband on the NBN. Some people are paying less, most people are paying about the same.''

According to Dr Nansen, one of the reasons most people did not end up paying more for the NBN was that some households substituted their landline telephone for a VoIP phone (which allows telephone calls to be made over the internet for free, as with Skype).

The researchers received funding from the Australian Communications Consumer Action Network (ACCAN), the peak consumer body in the telecommunications sector.