Customers signed up to news publications, dating apps and streaming services could be hit by higher prices at the start of next year, it was warned last night.
It comes after the Government unexpectedly brought forward plans to restrict rules around subscriptions.
Firms now say this gives them 'little to no time' to comply with the changes and meet the new deadline.
A source close to a coalition of businesses including publishers and tech firms said an abrupt decision to impose the crackdown in January rather than next spring as previously promised would force companies to bring their operations in line faster – costs they would then likely pass on to their customers.
Under a package of 'everyday fixes' to help ease the cost-of-living crisis, Prime Minister Andy Burnham said that from January, new rules would be put in place that would end what he dubbed 'subscription traps'.
These are where firms make it harder for people to cancel their subscriptions or have to renew them at a higher cost than initially advertised.
The rules will mean businesses will need to provide clearer information upfront about the cost of a subscription, regular reminders and make it easier to exit contracts.
A 14-day 'cooling-off period' will also be created to let people cancel subscriptions after a trial period ends or every time a long-term contract renews.
Mr Burnham estimated the changes would save around £14 each month per unwanted subscription.
But firms have warned that the measures are likely to backfire and force many companies to pass on higher costs to consumers.
In April, the Government, then led by Sir Keir Starmer, promised that the rules would not come into effect until spring 2027, so many firms that rely on subscriptions for large parts of their income were left blindsided by the decision to move the date forwards to the start of the year.
A coalition of businesses and trade organisations, which include newspaper publishers as well as representatives of the UK's tech and media sectors, said the 'rushed' announcement had broken previous promises and they now had 'little to no time to prepare' for the new rules.
'We are deeply disappointed that, despite repeated assurances about a proper implementation period, ministers have decided to rush forward with the new subscriptions regime, leaving businesses with little or no time to prepare,' the coalition said in a statement.
They added: 'Ultimately it is consumers who will be short-changed, as the businesses providing services enjoyed and relied upon by millions are left scrambling to adapt to an entirely arbitrary new deadline – diverting valuable resources that would otherwise go into building better products.'
Theo Bamber, head of the News Media Association, which represents national, regional and local news organisations in the UK (including the Daily Mail) said the 'drastically reduced' timeline for the new rules put a 'key growth area' for media firms at risk.
He also pointed out that subscription models were particularly vital for local news organisations which the Government has stated a desire to support, and were also 'crucial' to the success of Mr Burnham's wish to devolve more political power out of London to the UK regions.
Mr Bamber called for the Competition and Markets Authority, the watchdog which will enforce the new rules, to lay out an 'adjustment period' and 'support businesses' to help them comply with the new rules.