Royal Mail has put a cap on the number of stamps retailers can buy in an attempt to stop customers stockpiling cheaper stamps before a price rise on 30 April.
Retailers will only be able to buy 20% of their annual allocation during April to ensure customers continue buying stamps after the hike and the company's revenue is protected.
But demand has shot up after panicked customers panic-bought stamps at the cheaper rate and reports say many high-street chains are in danger of running out.
The cap means once retailers exceed their allowance they won't be able to purchase more supplies. But despite the ration James Eadie, spokesperson for Royal Mail, says: "There is a good supply of stamps across the country, we have more than adequate stock in place to meet customer demand."
The rise was brought in because Ofcom removed price controls on Royal Mail at the end of March after a 25% decline in the amount of mail being sent since 2006.
Prices for a first class stamp will shoot up to 60p, from 46p, and the price of a second class stamp to 50p, from 36p, at the end of the month.