Link is increasing the fee it pays cash machine operators to keep remote free-to-use machines available.
Operators will be offered up to £2.75 per withdrawal to persuade them to keep at-risk machines free.
“It is vital we continue to provide free access to cash to those who need it,” said Link chief John Howells.
But Jenni Allen of Which? said: “Boosting premiums for remote machines has so far not been enough to stop cashpoints closing around the country.”
Many of the machines are in deprived areas where cash use is higher, which means locals are hit if ATMs are withdrawn or a charge is introduced.
Last year Which? claimed that 300 ATMs were closing a month, although the consumer group’s analysis was disputed by Link.
Link, the UK largest ATM network, said last summer that machines in remote locations could receive an extra subsidy, particularly if they are threatened with closure.
Today it has announced a new super premium which will be introduced in April.
It will be offered to around 3,500 free-to-use ATMs that are currently 1km or more away from the nearest free-to use ATM, with between 50 and 100 eligible for the full £2.75 subsidy.
Currently, operators of eligible ATMs receive a top-up subsidy of up to 30p through Link’s financial inclusion programme.
“These premiums will further safeguard ATMs in remote and less well-off areas,” said Mr Howells.
One of Britain’s remotest cash machines is on Britain’s most northerly island, Unst.
It’s part of the Shetland Islands, north of Scotland and has an estimated population of 632.
Karis Burns, who works at P&T Coaches which houses the only cash machine on Unst, says: “It’s quite important to have a cash machine here, the only other place to get cash is at the local post office about half a mile away.”
She said the machine is used “about six or seven times a day, although in the summertime it’s used a bit more”.
The summer usage is boosted by tourists who visit Unst, although Karis admits: “We’re quite remote.”
The cost of taking out cash at the machine is £1.99.
According to Link, Britain’s remotest free-to-use machine is at Lloyds Bank branch in St Mary’s on the Isle of Scilly.
It’s 50km away from the next nearest ATM, at Penzance on the mainland, a ferry ride away.
There’s just one ferry operator which sails up to seven times a week, with the journey taking a minimum of 2 hours and 45 minutes.
Link’s move follows a row over plans for a phased reduction in interchange rates, the fee operators receive from banks.
The fee is being cut from 25p to 20p over the next three years but the move which led to accusations that “cash deserts” could be created as operators shut less lucrative machines.
There are more than 50,000 free-to-use ATMs across the UK – and the vast majority will not be eligible for the new super premiums.
Currently, around 3,500 ATMs are protected – because they are more than 1km away from the next nearest free machine or are located in particularly deprived parts of the country where access to cash is vital.
Around £100bn is spent in shops using coins and notes every year, according to the Federation of Small Businesses.
Its national chairman Mike Cherry said the launch of the super-premiums “highlight the fundamental failures of our ATM market”.
He said: “The Payment Systems Regulator must now intervene and help the industry formulate a long-term strategy for maintaining free access to cash right across the UK.”
Ms Allen of Which? Money agreed, saying: “What is urgently needed is for a regulator to be given a duty to protect access to cash, so that the millions of people who rely on it in their lives are protected from rapid changes through ATM and bank branch closures.”