Absolute Radio listeners can enter a competition to be in with a chance of spending Christmas with family or friends who live anywhere in the world.
Listeners are able to enter by telephone, or, if they fill in their details online at www.absoluteradio.co.uk, they will also be included in a second draw to win a Christmas package of gadgets worth £1,000.
The promotion, which was planned and bought by Mindshare, will use the taglines 'Handled With Care' and 'Christmas Made Easier' to link the activity to the Post Offices wider ad campaign created by Dare.
Stewart Fox-Mills, head of marketing at the Post Office, said: "At the Post Office, we understand the pressures of modern-day life and this is why we are changing to meet these needs.
"Christmas is an exceptionally busy time for everyone and this is why we have extended our opening hours and improved our Christmas online support. Christmas in the Post Office will be made easier for millions of people across the UK this year."
Katherine Knapp, head of promotions at Absolute Radio, said: "This will be a really engaging and unique promotion for our listeners and will place the [Post Office] brand at the heart of what will be an incredibly rewarding Christmas campaign."Follow @MaisieMcCabe