The "senseless" vandalism only served to highlight the mentality of a tiny minority of people in the community, who endanger everyone else, she said.
"We've had public meetings about lowering the speed limit, as well as media coverage around the issue, and not one person has seriously objected to the reduction in speed limit. Instead of engaging with this issue openly, however, this individual has chosen to carry out a selfish act of vandalism against the community.
"Our lives, and the lives of our children, cannot continue to be endangered by people like this. More than ever we need a safe, legally enforceable speed limit on the hill, and the authorities need to be diligent about enforcing it."
The fact that the vandalised sign was located near Kareponia Marae, the heart of the community, home to a kohanga reo and on the school bus route, was especially concerning.
"This person has shown complete contempt for the law, and complete contempt for those of us who live and work on the hill," she added. "I urge anybody who has information about this act of vandalism to contact the police today."
NZTA spokesman Darryl Walker said yesterday that he expected the sign to be re-erected, although it was not yet known whether the electrics had been damaged, or to what extent.