UK bank customers could pay up to £250m to withdraw their own money from cash machines in 2006, the Nationwide building society has predicted.
More than four in 10 cash machines charge a fee
In 2004 the private companies who install and operate charging ATMs made £140m in withdrawal fees.
In total, nearly 22,000 of the UK's 54,000 ATMs levy a cash withdrawal fee and increasing numbers are being put in newsagents and convenience stores.
Operators argue customers can choose whether or not to use their machines.
The spread of fee-charging ATMs has been rapid. Last year alone the number of machines rose 16%.
At the same time, the number of free-to-use ATMs has remained static.
This is partly due to some banks selling off their non-branch-based ATM sites to fee-charging providers.
"If this pattern continues, there is a real possibility that free access to cash will not survive other than at bank and building society branches and a few other locations such as main post offices," said Stuart Bernau, Nationwide executive director.
There has been a long-running controversy over the spread of fee-charging ATMs.
Opponents, including Which? and Citizens Advice, argue that charges hit people on low incomes hardest, as these people are more likely to make smaller, more frequent withdrawals and are therefore bearing a disproportionately large share of the charges.
Claire Whyley, of the National Consumer Council, said: " It is essential that people have easy and cost-free access to their money.
"ATM charges are simply another example of the poor paying more - in this case they are paying a high price just to access their own money."
But fee-charging ATM firms have argued that they are providing a service and that consumers have a choice to use their machines or not.
Last March, the parliamentary Treasury Select Committee issued a report calling for clearer warnings on fee-charging cash machines.
But in its response to the committee's report, the government gave charging ATMs the all-clear, pointing out that the vast majority of fee-charging ATMs were in locations where there had never been a free cash machine.