"That may well have been a misunderstanding, but the behaviour of the group to then use one of the bedrooms as a toilet was inexplicable," Mr Sutton said.
"It caused a health risk to my staff, but in general is just disgusting behaviour and not something we would want other tourists to think was acceptable anywhere in New Zealand."
In another incident where former property owners had been paid out for their property by the Crown, nearby residents had heard that a large "farewell bonfire" was being planned for the house.
Cera uses motion-sensor security cameras on many properties that has helped with several criminal investigations. But it has reached the point where staff have needed to keep a video record of some of their encounters in case that could also help police.
Settled properties in the red zone are Crown-owned, and not abandoned, Mr Sutton said.
"It's not a free-for-all for anyone to use or destroy them, and we need to make sure we work through the insurance issues and EQC issues before properties are demolished or relocated, so that the tax-payer gets the best value out of the money being spent."