When it was suggested that it was frightening to think how easy it was to gain access to a power station, Mr Campbell said: "Not everybody can actually do it and we’re actually very highly trained and we research the activities very well."
When further pressed about how the activists managed to get in, he said there was, "No comment".
On Wednesday, police received reports of people taking photographs of the nearby Vales Point Power Station, prompting speculation that it could have been Greenpeace members preparing for their protest.
Tuggerah Lakes Local Area Commander Superintendent Geoff McKechnie said the group had gained access yesterday by cutting through a wire perimeter fence.
He refused to answer questions about Delta Electricity’s monitoring of the power station fence lines, citing security concerns.
"They do have security processes in place and we will be working with Delta to improve those security processes," he said.
Yesterday a Delta spokeswoman said the incident would be investigated, "but it really is now a matter for the police".
Power station staff were evacuated during the protest but power production was not interrupted.
Police eventually cut free the protesters, who were later charged with a range of trespass and malicious damage offences.