Tunisian club Esperance vow not to "give up their rights" while Wydad Casablanca's President Said Naciri told BBC Sport he is waiting "to make a final decision".
The comments came after the Confederation of African Football (Caf) ordered Esperance to replay the second leg of the Champions League final.
The Tunisians have also been ordered to return the trophy.
Esperance led 1-0 in Friday's second leg but their Moroccan opponents left the pitch after an equaliser they scored was disallowed.
Wydad wanted the video assistant referee to check if the goal should stand but the system was not working.
A Caf statement said on Wednesday "conditions of game and safety were not met" and that the second leg should will be replayed at a neutral venue.
In a statement issued on Facebook, Esperance said they "will not give up their rights and will defend them in every legal way possible".
The club added: "We were shocked by the decision and will hold an emergency meeting in the next few days to appeal this decision with the specialised International authorities.
"We will take all necessary measures to defend the team's rights in every legal aspect possible."
Walid El Arem, a member of Esperance's executive committee, said in a video released by Foot24: "This is a dangerous unprecedented event. There is no law backing up the decision to replay the game.
"All I can tell Esperance fans is that we will not give up, we will take the matter to Cas (the Court of Arbitration for Sport)."
Riadh Touiti, head of the legal committee at Esperance, said in the same video that "Esperance had nothing to do with VAR not working that day", adding: "Caf officials had no business being on the pitch that day. Their presence on the pitch created a commotion and encouraged Al Wydad players to do what they did."
Esperance said they are waiting for an official letter from Caf informing them of the decision before proceeding with the matter.
Reaction from Morocco
Wydad are also waiting for the full ruling before deciding their next steps.
"We haven't received any written decision yet - we have only just read the Caf decision online so we are waiting for their official letter," club president Naciri told BBC Sport.
"Then we will call for a meeting with our lawyers and discuss their decision legally. Then we will announce our final decision."
Wydad's Nigeria winger Michael Babatunde is relishing the chance of a replay.
"This really excites me to be honest, the controversial way the game in Tunisia ended wasn't right," he told BBC Sport.
"Caf has taken the right decision now by ordering a replay at a neutral venue because the continent deserves it.
"This replay is the best way to determine the true champions of Africa and not the way it ended in Rades."
Wydad Casablanca had put the controversies of the African Champions League second leg behind them to clinch their 20th Moroccan league title on Tuesday.
The championship was won with a game to spare with a 4-1 win over Olympique Khouribga which put them six points clear of city rivals Raja.
"We've won the league title and winning the Champions League trophy was the target at the start of the season," he added.
"Now we have another chance to do it. The players are delighted and our fans are happy because a chance has been presented to have another go at it."