Portsmouth's former owner Portpin has asked the Football League to clarify its position on considering new bids for the club.
The League said it would not consider offers other than that of the Pompey Supporters' Trust (PST) after this week rejecting a bid fronted by football financier Keith Harris.
But Portpin, led by Balram Chainrai, claims the League's stance is unlawful.
And in a statement it suggests the Harris bid is better for creditors.
The PST's takeover is dependent on gaining control of Fratton Park, which is owned by Portpin.
The two sides have been unable to agree on a fee for the ground, with the valuation set to be determined in the High Court before 19 April.
“There are now at least two offers for the club, one from the Supporters' Trust and one from a consortium which includes Keith Harris, and legally they must both be considered on their merit”
Portpin claims the Harris bid would mean it received £6.3m for the stadium, as opposed to the £3m currently being offered by the PST.
It claims ruling out consideration of other offers "unlawfully limits the ability of the administrator to fulfil its role in securing the best terms for creditors".
And Portpin has warned that if alternative bids are not considered, the League "will leave itself exposed to legal action for damages from creditors which could amount to millions of pounds".
A spokesman for Portpin said: "We have made clear that we are agnostic as to the source of the solution for Portsmouth Football Club and welcome whichever bid offers both the best deal for the creditors of the club and provides the highest degree of certainty for the supporters in bringing Portsmouth out of administration.
"There are now at least two offers for the club, one from the Supporters' Trust and one from a consortium which includes Keith Harris, and legally they must both be considered on their merit. After more than a year of uncertainty, this process must be brought to a close.
"We are today calling on Greg Clarke, chairman of the Football League, to commit publicly to the Football League reviewing any bid that is put to it for approval by the administrators.
"If Mr Clarke fails to provide everyone with the certainty that is needed on this issue, the Football League will have no option but to accept its share of the responsibility for the damage that could be caused to Portsmouth Football Club, its creditors and the other members of the Football League which may not end up recouping any of the money owed."
Pompey Supporters' Trust spokesman Colin Farmery told BBC Sport: "As ever, Portpin like to have their say on the Pompey situation but you would have thought by now they would get the message that the Football League only want to deal with the PST bid.
"It's interesting to see Portpin seem to have considerable knowledge of the details of the Harris bid, considering he was assuring everyone his bid was independent of Portpin and that there would be no legacy issues as a result.
"The fact that Portpin, under this bid, are going to get £6.3m for Fratton Park demonstrates once and for all what this really about. It's about Portpin taking more money out of Portsmouth Football Club.
"The PST bid ensures Fratton Park remains in the hands of Portsmouth Football club, which is what all Portsmouth fans want."