Ofcom plan to remove price caps on first-class stamps and raise the price limit on second class to as much as 55p.
Ofcom which has taken over regulation from Postcomm said said its proposals announced last October, were:
"designed to make sure UK consumers continued to benefit from an affordable, universally-priced postal service six days a week, at a time when postal use was declining as many people had turned to new technology".
The cost of a first-class stamp is currently 46p.
The Royal Mail would be allowed to set this price at a level it considered to be appropriate and competitive.
The only price capped would be the charge for second-class letters, which was just 19p in 2000 and is currently 36p.
Ofcom has proposed that this should increase to between 45p and 55p, with Royal Mail suggesting the price should be at the higher end of this scale.
MP's are urging the public to stock up on their Christmas stamps now to avoid the 53% proposed increase.
The Royal Mail say they are:
"awaiting the outcome of Ofcom's consultation on its proposals for future regulation of UK postal services before announcing stamp prices for 2012"