The big four banks' rush to scrap ATM fees for customers of other banks has been hailed as a win for consumers, but bank critics on Monday warned it was not enough to prevent gouging by other owners of ATMs outside the major banks.

Treasurer Scott Morrison is happy to give CBA a "pat on the back" for their decision to remove ATM fees for anyone withdrawing cash.

Industry sources also said several banks had been in talks about forming a "utility" to help lenders manage costs of their ATM fleets, as customers withdraw less cash, cutting revenue and adding to pressure to shut machines. It is understood Commonwealth Bank, which led the charge on Sunday in cutting its fees, had pulled out of the talks last year.

Even though the big banks control about 80 per cent of the market in retail banking, they own less than 40 per cent of the ATMs.

About 55 per cent of all machines are owned by specialist ATM operators, the Reserve Bank said in the latest public figures of 2015. These machines are often located in pubs, convenience stores, or at festivals, and tend to charge $3 or more for a transaction. 

The Greens last year pushed for a broad-based ban on "excessive" ATM fees, as well as banning banks from charging customers from other banks, but it was not supported by Labor or the Coalition.

Greens leader Richard di Natale on Monday welcomed the big four's decision to dump "greedy fees" but re-iterated the party's call for a broad ban on "excessive" withdrawal fees.

"The reality is that as long as half of the ATM's in this country are owned privately, we're going to have a major problem with extortionately high withdrawal fees," Senator di Natale said.

Labor Senator Sam Dastyari also said the government should look at regulating to make sure all lenders and specialist ATM businesses also lowered or removed their fees. Senator Dastyari said some specialist ATM businesses outside cities operated in a "monopolistic" fashion, that allowed them to "gouge" customers. 

"I think the government should now look at what can be done to either ban this completely or at least put some regulation in place to say this should not be more than cost recovery," he said.

Such a move could be a further blow to an industry that has already been forced to consolidate as customers withdraw less in cash, and the banks' move at the weekend could compound the challenges facing specialist ATM businesses.

The largest ATM owner, Cardtronics, owns about 11,000  machines in Australia, or more than a third of the total. Its managing director for Australia, Matthew Thomas, said it would talk with its partners after the major banks' latest changes.

RediATM, which is owned by payments company Cuscal, also has more than 3000 machines across the country in partnership with 90 members including NAB. NAB's machines will no longer charge fees, Cuscal said, but other members would set their prices independently.

CBA's Bankwest ATMs will be excluded from the changes, meaning hundreds of Bankwest machines in 7-Eleven stores in the east coast will continue to charge fees to customers of other banks.

Bank of Queensland on Monday said it too would no longer charge ATM fees at machines in its branches, while Suncorp said its ATM fees were under review. Bank of Bendigo also indicated it would talk with partners before making a decision on ATM fees.

Meanwhile, banking sources on Monday said there had been talks between lenders about forming a "utility," which would allow banks to cut the unpopular fee and also rationalise the number of duplicated machines. Under the plan, banks would be able to share their servicing costs for their ATM fleet, and potentially be able to prevent some machines from being closed earlier.

Before the weekend's announcements, several banks including ME, ING Direct and Macquarie already provided bank accounts that allowed their customers to withdraw cash from other banks' ATMs at no charge.

The financial impact of the big four's scrapping of ATM fees is likely to be small for the banks, and ATM fee revenue has been falling. 

Morgan Stanley analyst Richard Wiles said in a note to clients the impact of the changes would be "immaterial," at less than $50 million for each of the major banks.

The change has put the spotlight on other bank charges. Choice head of campaigns Erin Turner highlighted growth in banks' credit card fees, and their failure to drop interest rates on credit cards in recent years despite lower funding costs.

"They should be dropping credit card fees and dropping credit card interest rates," Ms Turner said.

Treasurer Scott Morrison predicted there would be "more news to come" on bank fees, pointing to those charged for contactless payments on credit cards.