Numerous repairs have been made to the platform, but problems remain. The carpark was built in 1982.
Auckland Transport is trying to extend the platform's safe, usable life by limiting the weight it carries.
After a new sign stating the ban was erected several months ago, Ōrākei council member Desley Simpson said it applied to "Remuera tractors".
This week she said many drivers of overweight vehicles had continued to flout the ban after the new sign went up, but this had ended since a security guard had been posted to the carpark.
As signage is not working as well as it should AT have a security guard in place at Remuera’s Clonbern Rd carpark...
Posted by Desley Simpson on Monday, 29 October 2018
An Auckland Transport spokesman said, "The Ōrākei Local Board asked Auckland Transport to have someone on site to inform locals about the carpark."
He said the carpark remained safe to use, provided vehicles weighing more than 2000kg stayed off the upper deck.
The carpark is being monitored regularly for Auckland Transport.
"A report is due shortly from a firm of structural engineers and further decisions will be made after AT receives that report."
The carpark is at risk of closure if overweight vehicles park on the platform.
"Keeping the weight lowered is the only way the upper level can remain open," the spokesman said.