Lake Hawea Community Centre president Andre Meyer said he was notified about the damage last Tuesday.
"It could not have been a young kid because of the amount of force," he said.
In both toilets a rock had been smashed through the window with enough force that it left a large dent in the wall opposite.
Mr Meyer suspected the rocks directly below the window were the ones used to cause the damage, so the remaining rocks have now been relocated.
"We do have CCTV cameras at the centre, but not at that end by the library, because it looks out on to the nearby children’s playground and we wanted to be respectful of people’s privacy," he said.
Now, because of the incident, the committee was considering installing cameras.
It was disappointing the centre had been hit, especially as it was a community asset and occurred when money was being invested in the development of sports and youth upgrades, he said.
He estimated the repairs would cost about $500.
Those involved in the vandalism are still unknown, but the police have been notified.
By: Aspen Bruce
