Millions of Australian homes and businesses are being collectively charged an annual $3.1 billion "Telstra tax" for using its services, according to a report by the Centre for International Economics.

The research body said that Telstra customers pay an average of $20 per month more for fixed-line services compared to its competitors while its mobile subscribers pay a $9 monthly premium for mobile subscribers with rural communities slugged with higher fees.

Vodafone's chief strategy officer and corporate affairs director, Dan Lloyd, said this was the first time anyone had been able to look at what was "happening under the hood". Credit:Louie Douvis

The net result is Australians paying the equivalent to a 15c per litre increase in petrol prices just for using Telstra's phone and internet services, it claimed.

The CIE is a research group whose findings have formed the basis of key government reports such as the Vertigan Review into the national broadband network. Its latest work, Australia's telecommunications market structure - The price premium paid by consumers, has been paid for by Telstra's direct competitor Vodafone Hutchison Australia.