"I don't think that it is impossible that we could be in a deal mode in 2013, but personally I think it is probably more likely to be the first quarter in 2014. My preference and I believe the government's preference is a float," she told Reuters on Tuesday.
The news comes on the day that the postal service has been told it can set prices for most of the letters and parcels it delivers under a new seven year framework.
As a result from April 30 the price of a first class stamp will rise from 46p to 60p while a second class stamp will also rise 14p to 50p.
Royal Mail made a £41m operating loss on letters and parcels in the six months to September 25.