Portsmouth have been issued with a winding-up petition by HM Revenue and Customs.
HMRC sources have confirmed to Press Association Sport that the petition over an unpaid tax bill, which the club's administrator says is £1.6million, has been sent to the troubled npower Championship club.
"Ensuring tax is paid on time should be at the centre of a football club's business strategy just like any other business," said an HMRC spokesman.
"Anyone that regards paying tax as an optional extra, or that uses tax collected from employees or customers as working capital, is potentially heading for trouble.
"While a winding-up order is a last resort, there is little HMRC can do for a business - be it a football club or not -
whose viability is dependent either on not paying the UK taxes to which they are liable, or on special treatment not available to other customers with similar tax affairs."
The extent of Pompey's latest financial problems were revealed after Italian businessman Joseph Cala pulled out of a deal to buy the club on Friday.
Andrew Andronikou, the joint-administrator of the club's parent company Convers Sports Initiatives, said the club was unable to pay a bill of £800,000 in December and that another £800,000 payment was due on January 20.
The club have been looking for new owners since Convers Sports Initiatives entered administration in November.
Michael Appleton, the Portsmouth manager, has admitted he expects to have to sell players from what is already the smallest squad in the Championship.
In February 2010 Pompey became the first Premier League club to enter administration with debts of around £60million and were deducted nine points, which saw them relegated from the top flight.
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