Manager Darryl Evans said the 2.5m by 1.5m window, one of two on the hotel's facade, had a large rock, the size of a football, thrown through it.

"It happened between Friday, November 28, at midnight and the following Saturday morning," he said.

"We didn't even realise until someone driving past knocked on the door.

"I just took one look and said `you're joking'."

Mr Evans said the community and the hotel's regulars were upset by the incident.

"Everyone has said it couldn't be a local because no one would do that around here," he said.

"These leadlight windows are among the last around and have been here since about the 20s.

"They are a part of Daylesford, they're an icon."

Mr Evans said leadlight specialists in Ballarat had been contacted and would recreate the window to the best of their ability.

"Who knows how long it's going to take - and whether they can find the same glass again," he said.

Mr Evans said the window, which has provided the inspiration for the hotel's logo, would cost thousands to replace.

"Of course we're insured and it's not about that - we just hope that someone knows what happened and contacts the police."

Security cameras will now be installed around the outside of the hotel.