The report included thorough examination of cracks in the pumice walls of the building.
"The thing to remember is we are dealing with a building that was built in 1908, when reinforced concrete wasn't around back then, certainly not available," says Mr Brown.
Engineers believe repairs are required to the roof of the museum, along with substantial timber and joint restoration.
In the year prior to its closure, the museum was visited by nearly 120,000 people.
But Mr Brown says the museum mandate is still being fulfilled. "Our events and programmes are continuing to run in other venues around the city. Our education programme is also continuing to run. So despite the closure, we have still managed to provide services to about 22,000 visitors over the last period."
It is estimated that the closure of the building has resulted in $1.5 million dollars in lost revenue.
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