The Otago Regional Council flood work will continue to block part of Dundas St until its expected completion in October.
At a council committee meeting yesterday it discussed a staff report which said unauthorised people continued to enter the site, despite fencing, signage, security guards and publicity.
"They are exposing themselves to the very real likelihood of serious harm or death, and this is a serious concern for staff and the contractor."
Council operations general manager Gavin Palmer said the council was making "continued improvements" to the security and safety of the area.
However, it could not "physically stop people who are determined" to enter.
There was a spike in incidents with "things happening in town", he said.
The council had invited members of the Otago University Students' Association to be escorted around the site next week to fully understand its dangers.
Cr Michael Deaker said he had been holding his breath since the work started.
"It's inevitable some drunken twit is going to fall in at some stage."
He commended the work of Dr Palmer and other staff in making the site "as safe as possible".
