The council yesterday announced the council-owned complex, which opened in 2009, needed between $500,000 and $750,000 worth of repairs to the deck of its public car park.
That included stripping and re-finishing the deck and steel screens, as well as replacing two seismic joints which had "reached the end of their serviceable life", council property services group manager David Bainbridge said.
Two other seismic joints had been replaced already in March last year, after they began leaking and allowing water into office space below, he said.
The latest work would be carried out in stages, starting with a two-month closure on April 1, he said.
The south side of the car park would remain open to leased car park customers during the work, but the north side - home to about 40 public car parks - would be off limits until June, he said.
The second stage of repairs would be timed for spring, when the weather began to improve, and would require a further closure of the public car park, lasting about six weeks, he said.
Mr Bainbridge said the work did not mean the car park or complex were earthquake-prone.
The name of the seismic joints was "somewhat misleading" and the only real concern was further deterioration of the joints allowing water in, he said.
"It's not letting in any water to office spaces this time, but we can see that it's just starting to leak. If we don't do anything that will happen, but it's not causing a problem at the moment."
He rejected any suggestion the work showed there was something wrong with the building, saying a 10-year lifespan for the items needing replacement was "pretty reasonable".
The complex has had repeated problems since opening in 2009, mainly relating to its glass panels.
In 2011, a glass ceiling panel inside the mall spontaneously shattered, showering two members of the public below in debris.
A protective film was later added to the ceiling in 2012 to hold broken glass in place if a panel shattered.
But, in 2015, a 6m by 3m decorative glass panel on the building's facade split into two pieces which fell, minutes apart, on to a veranda below.
Then, in 2017, another glass panel on the building's facade also shattered and fallen on to the entrance veranda below.
