The York Dungeon is currently closed following some of the worst floods in the city for more than a decade.
The Merlin Entertainments-owned attraction is two-thirds affected by the River Ouse bursting its banks earlier this month.
A spokeswoman said: “The attraction is currently closed while a full assessment of the situation is undertaken, working with the local attraction team and independent insurers.
“The company is working to clarify the situation as quickly as possible but as yet we have no firm date for reopening.”
The York Press newspaper states that the closure is likely to affect the Dungeon’s typically busy Halloween period.