Ofcom is expected to say further price cuts would be too drastic in the developing mobile phone market. The firms are understood to have claimed they have invested in services and deals for consumers and say competition is already bringing prices down and should generate further falls.
The last time the regulator ordered call charges to be reduced, there was a long battle with the operators, who refused to accept the cuts and insisted the decision be referred to the Competition Commission.
After the commission backed the regulator, they sought a High Court judicial review to block the move. Experts think this may also be a factor in the decision to delay further cuts Ofcom is also embroiled in a separate but parallel dispute with 3G operator '3' over whether it should be covered by price controls.
An Ofcom spokesman said: 'The review will look at the appropriate level of regulation going forward and part of that will be about protecting the consumer.'
Some in the industry are said to want the termination charges to be completely deregulated, allowing firms to compete on these rates as well as call charges.
But critics say this would be wrong and Ofcom is thought to have ruled it out. A spokesman for the National Consumer Council said: 'The market is not sufficiently competitive and that's why we have controls. Removing these regulations would not be appropriate.'