Safety issues were found on the high speed ferry, which operates to the Channel Islands, during a Maritime and Coastguard Agency (MCA) inspection.
Condor Ferries said all the matters highlighted "have now been rectified".
It said the MCA would re-inspect the ferry on Friday and, if completed satisfactorily, the Liberation would return to service on Saturday.
A MCA spokesman said inspectors found 11 deficiencies with four grounds for detention - the main engine operation, steering gear operation, fire doors and ISM (International safety management code).
He said: "Release of the ship will be made only when MCA's inspectors are satisfied with the actions undertaken by the company."
MCA findings - Major failings
Other failings
The company has chartered a freight ship, MV Arrow, so the conventional ferry Commodore Clipper can concentrate on passenger services.
It said its plans for Friday and Saturday meant "freight services are unaffected" and would allow "around 70% of our passengers to travel on their expected day - albeit many of them on a different ship and/or at a different time".
The firm's other high speed ferry, Condor Rapide, is at Falmouth in dry dock for annual maintenance.
Friday's sailings
The Condor Liberation ferry, which was detained in Poole, may be allowed to carry passengers again this weekend.