Portsmouth's financial plight means they may not be able to complete the current season, according to club administrator Trevor Birch.
Birch says Pompey, who entered administration in February, will not receive parachute payments from the Premier League as they will go straight to former owner Sacha Gaydamak.
In a statement on the club's official website Birch said: "Following our discussions with the Premier League and Football League over the past few days, it has emerged that Portsmouth football club is unlikely to receive any further parachute payments or other league funding.
"We had previously stated that there was a real danger of the club running out of cash before the end of the season.
"The risk of this happening increases substantially without the money from the football authorities.
Clock is ticking
"Unless something significant happens, there is a real possibility that we may not be able to fulfil the season's fixtures.
"One potential issue appears to come from the assignment of £2.2million of parachute payments that was made by the old company to a previous owner.
"We have instructed lawyers to challenge this, but the process may take time."
Birch remains committed to saving the cash-strapped club, but admits "the clock is ticking" to find new owners.
He added: "As you'd expect, several people have got in touch with us since our appointment as administrators and made enquiries about buying the club.
"We are assessing every case and will make contact with anyone that we believe could be a serious bidder over the next few days.
"Any potential bidders will need to be prepared to make a major investment in the club because the outlook for next season looks challenging unless we can sell some players in the summer."
Pompey were deducted 10 points in February after going into administration for the second time in two years.
Birch was forced to loan top scorer Erik Huseklepp to Birmingham to trim the wage bill and also announced 30 redundancies at the club.
They are currently second from bottom, five points from safety, and face Middlesbrough at Fratton Park on Saturday.