The order was made against the Prime Minister on October 26, according to Private Eye magazine.
After it cited an unpaid bill of £535, Downing Street are now trying to cancel the county court judgement and have claimed it was “totally without merit”.
A No.10 spokesperson said: "An application will be made for an order to set aside the default judgment, to strike out the claim and for a declaration that the claim is totally without merit.”
Earlier the Prime Minister's official spokesman said: "I can confirm it has nothing to do with a refurbishment of the Downing Street estate where all such bills have been duly paid either by the government or the Prime Minister, personally."
County court judgments are issued in England and Wales when people fail to repay money they owe.
The UK Government website explains: "If you get a judgement, this means that the court has formally decided that you owe the money.
"If you're late with your payments, you could be taken back to court and you may have to pay extra costs.”
Banks and loan companies can also use the information to decide whether to issue credit or loans.
Not paying can even see a bailiff visit your house.
Labour’s deputy leader Angela Rayner has now labelled the reports “deeply concerning”.
She said: “Another day, another report of deeply concerning irregularities about the renovation of Boris Johnson’s flat.
“This is not about Boris Johnson’s personal finances. The record speaks for itself that he has already broken the rules on declaring his financial interests and he is already under investigation regarding potentially illegal wrongdoing.
“The issue of debt when it comes to the Prime Minister is whatever debt of gratitude Boris Johnson owes to the Tory donor who paid to renovate his flat, and what this donor or donors were promised or expected in return for their generosity.”
It comes less than a fortnight after a Conservative donor claimed he was donating £58,000 to the party in relation to Downing Street flat refurbishments.