The series of ads are presented by Channel 4 property specialist Amanda Lamb and include three challenges related to home finance and property.
The fast-turnaround spots feature challenges that are solved in less than a day and played out within ad breaks across the week.
In the first spot, Lamb speaks to a couple looking for a house in Bristol, and sets out to find them a property the same day.
The concept was created by the Post Office’s retained media agency Mindshare, which also brokered the deal.
It is part of the Post Office’s ‘Handled With Care’ campaign and will highlight the company’s financial services expertise and product range, including mortgages and savings.
The spots were directed by ‘Made In Chelsea’ and ‘The Only Way Is Essex’ director John Pereira.
The challenges are being set by members of the public, chosen from more than one thousand applications via the Channel 4 website.
Martin George, commercial director at Post Office, said: "The Post Office 24-hour challenge is the ideal way of demonstrating our award winning range of financial services products."
Updates to the challenges will also feature on Post Office’s online and social platforms as well as in Post Office branches.
The director was John Pereira, through the production company Prescription.