The British government has been in talks with the Queen's advisers to discuss ways of ensuring the monarch's head remains on postage stamps, if the mail service is sold.
The coalition government plans to sell up to 90% of the Royal Mail's letter delivery business.
Business Secretary Vince Cable said in September that a foreign company could acquire Royal Mail.
Postal Services Minister Ed Davies says he approached Buckingham Palace after learning that draft legislation does not stipulate that the Queen's head be shown on every stamp.
I think it's very unlikely they would - because, after all, it's a very powerful brand, he told BBC television.
The Mail on Sunday newspaper says the monarch's head has appeared on every British postage stamp since their invention in 1840.