It also found that 53 per cent of people do not pay their card off in full at the end of each month.
Speaking about the research, Post Office lending director Gary Fitton said: "Typically January is the time of year when people struggle with their money the most.
"Many people have over-stretched themselves over the Christmas period and have little choice but to use their credit card in the new year."
The research by the Post Office came after the Consumer Credit Counselling Service urged consumers in the UK to budget for the first few months of 2008.
Spokesperson James Ketchell said the public should also focus on improving their credit card debt situation.
Click here to run an energy price comparison, and see if you could be paying less for your gas and electricity.