Birkhead said the job was not easy.
"Because of the challenges of working around all the existing people in there, it will be after Christmas that all the maintenance is completed," Birkhead said.
The shopping and office precinct is being painted 11 different colours after a new colour scheme was designed, he said, to freshen the place up and give the different precincts their own character.
"In leakies, you always find things you don't expect but the real challenge was working around the existing retailers and restaurateurs. We couldn't start early because people go there for breakfast nor could we work late as people are in the bars and restaurants around there. So that meant health and safety issues and how we got enough time in the day to do the job. That was the real challenge. It was more like keyhole surgery rather than open heart surgery - done in a tight time frame each day.
"We had to build bridges and platforms and protection over the top from the weather and underneath to protect the retailers and restaurateurs so the tradespeople were sandwiched in between - painters, carpenters, tilers, usual building trades people," Birkhead said.
In 2009, a report by building consultant Alexander and Co showed extensive repair work was needed.
Tony Allsop, of property managers and consultants Colliers International, said in July that the owners of properties there won $3.4 million for repairs from builders Multiplex and others.
The money had been paid last year after mediation, he said.