This follows the board of trustees earlier considering their use in a bid to stamp out bullying at the school.
The $15,000, 14-camera system was installed last month with Ministry of Education property services funding.
Services manager Mel Tudor said the cameras were installed as a vandalism deterrent. At a board of trustees meeting in December, a decision was made to investigate installing cameras in response to bullying allegations at the school.
Board chairman Shane Boyle refused to comment on the issue when contacted yesterday.
Mr Tudor hoped the cameras would prevent "annoying vandalism", such as things being kicked around or tables thrown around.
The school wanted to deter pupils and visitors from vandalism and had adopted a "zero tolerance" policy.
If the school was shown as not tolerating the "small things", issues would not worsen, he said.
The school was often used as a thoroughfare into and out of town, and the cameras would allow school property, and those who accessed it, to remain safe.
However, the school did not have a "serious problem" with vandalism, Mr Tudor said.
The cameras could also be used to monitor pupils' behaviour during the day.
"During the day, we could look at it if we felt there was something to look at."
The cameras were in their third week of operation and "there is nothing on them we would have been concerned about at all", Mr Tudor said.
The cameras operated on a network system and were motion-sensitive.
When movement was detected, the cameras started recording on to a hard-drive which could store about four weeks' information.
Security cameras were also installed at John McGlashan College's boarding house and Edgar Learning and Information Centre, college principal Mike Corkery said.
"We can't supervise people if we can't see them," he said.
Nine cameras in the boarding house acted as a deterrent against theft and bad behaviour.
Three incidents had occurred since the cameras were installed in 2000, one of which was a "squabble between two boys".
The cameras allowed the school to get to the bottom of the issue quickly.
The 14 cameras in the learning centre were used to deter "strangers hanging around", vandalism and burglary.
Cameras were not monitored all the time, but footage was looked at if an incident occurred, he said.
"It's not that we are looking at them; it's that they are there."
Otago Secondary Principals Association chairman Philip Craigie was not aware of any other secondary schools in the region using security cameras permanently.
On occasion, his school, Kaikorai Valley College, had used them temporarily to target areas where "undesirable behaviour" was occurring.
