ASTA is calling on Disney Cruise Line to reconsider its cap on commissions for onboard bookings, which was implemented late last year.
The agent association said a survey conducted by ASTA shows 93% of agents are "very" or "somewhat" concerned by the policy. It said 70% of the agents are recommending or will recommend another cruise line where possible.
For bookings made on board, Disney capped commissions that once ranged up to 16% depending on volume, to just 10% across the board.
The survey said 68% of agents say their customers are open to booking with cruise lines other than Disney, while only 2.5% are not at all open to considering another line.
"Our agents will book what their clients specifically request, whether that is Disney or any other cruise line," said ASTA president and CEO Zane Kerby. "However, travelers often rely on their trusted travel agent to guide them through their vacation choices, and because of the breadth and quality of cruise inventory available, agents have many alternatives to suggest."