Visa, which commissioned the study, said of the 400 cardholders interviewed, one in five believed they were worse off since the Reserve Bank scrapped its "no surcharge" rule three years ago, with almost half of those surveyed having paid a surcharge for at least one credit card transaction, compared with 34 per cent 12 months ago.

And far from customers receiving the millions of dollars in savings the Reserve Bank predicted with its 2003 reforms to the Australian Payments System, merchant price-gouging and profiteering was on the rise.

"The results speak for themselves," said Visa's Australian director of corporate relations, Andrew Woodward. "The number of people experiencing surcharging in the past three years has trebled."

The size of the surcharge levied by some retailers was also unreasonable, Mr Woodward said, and did not reflect the cost of an individual card.

While the surcharge for a Visa or MasterCard might be 1 per cent and for American Express 2 per cent, retailers were "rounding it up" to 3 per cent across the board.

Visa's survey also found that more than a third of cardholders said their reward programs had worsened since the reforms.

The Reserve Bank is not commenting on Visa's claims.

Russell Zimmerman, chairman of the Australian Merchant Payments Forum, dismissed the survey as small and unrepresentative, and rejected accusations of profiteering. "The retail market is terribly competitive and the cost savings have been handed on to consumers," he said. "But at same time other costs to the retailer have increased."