Portugal's finance minister Fernando Medina told the country's parliament that the government sacked the chief executive of TAP Air Portugal in March before the move was legally assessed.
The comments came ahead of potential court action after the ousted chief executive Christine Ourmières-Widener described her sacking as "illegal".
She was pushed out along with chairman Manuel Beja after a ruling that a TAP severance payment to former board member Alexandra Reis was also illegal.
The finance minister's remarks came after other ministers said the government had been given legal opinion on the removals of executives.
Opposition parties accused the government of "incoherence" and called for Medina to be sacked.
Lisbon hopes to privatise the flag carrier, with Lufthansa, International Airlines Group and Air France-KLM among the would-be suitors.