The European governing body is pondering alterations to both their club competitions and will make a decision in 2014.
Another proposal being looked at is to award Champions League qualification to the winners of the Europa League, and possibly even the runners-up too, in a bid to boost interest in the second-tier competition.
Uefa president Michel Platini said: "There is an ongoing debate to determine what form the European competitions will take between 2015 and 2018. We talk, and we will make a decision in 2014. There is nothing decided yet."
A 64-club competition would see as many as seven English clubs and five Scottish teams entering at various stages of the qualifying rounds.
Platini also blasted Fifa president Sepp Blatter for dismissing his idea of extra officials behind the goal-line as being too expensive. Uefa are continuing with the five officials, and Platini said that the cost was minimal compared to goal-line technology.
He added: "In our Uefa competitions, if you want to put in goal-line technology it costs us €32million in the first year and €54m over five years. Referees, it costs us €2.3m."