The mayor was given permission from council around the same time he was applying for a resource and building consent last year to build a retaining wall and for earthworks. The new fence will have a locked gate so council staff can access the bank.
Allen was particularly concerned about people falling down the slope after UK tourist Sean O'Connor entered a private property from a road reserve on Anglesea St and fell 6m to his death in 2015. The coroner's report, released in 2016, into his death did not recommend council fence the road reserve because the circumstances were "unique and unlikely to be repeated".
The mayor spoke to the Herald before it was discussed at council growth and infrastructure meeting today. The chairman raised the issue to be transparent after the Herald started asking questions.
King told the Herald it was a "goodwill gesture" to address a safety issue. "This is about somebody who died last year and I'm trying to stop that being repeated in my backyard in this part of the city.
"I did it through the proper processes, got permission, got consent from the neighbours and the fence went up at council specifications at no cost to the city.
"There were no special privileges here... it didn't require a consent."
At today's meeting the general manager told councillors he would treat any other member of the public the same and look at it on a case-by-case basis.
Councillor James Casson pointed out there would be a lot of other similar safety risks in the city, while councillor Paula Southgate was given reassurance other members of the public would be treated the same way.
Deputy mayor Martin Gallagher said he did not think there had been a conflict of interest.
King declared a conflict of interest and left the meeting.