The Tauranga City Council has begun the job of moving almost 80 percent of its staff after toxic black mould was found in several parts of its main buildings.
Four types of mould, including black mould, were found in the council's four Willow Street offices.
The mould was discovered in mid December after an employee complained about feeling sick every time he was at work. Since then, at least 10 more employees have come forward with asthma-like symptoms or skin irritations.
About 400 of the 520 council staff have had to move desks because of the mould problem.
Since it was discovered, workers have either been relocated to other parts of the building, taken paid leave or have been working from home. However, late last week they started moving into two new buildings the council has leased for nine months.
Project director Terry Winyard said the staff needed to move while the council worked out what could be done next.
"It's certainly had its challenges, there's no doubt about that."
Mr Winyard said so far carpets and furnishings had been removed from contaminated offices.
"It covers a large area and there are lots of pockets of contamination so we have to treat it with care," he said.
Mr Winyard said they were not considering demolishing the building and starting again at this point, though it was also too early to tell whether the offices could be fixed.
"At this stage we're not considering abandoning the buildings but we'll work our way through that as we move on."
A weather-tightness survey is being carried out and results are expected by the end of March.
The mould problem is estimated to have cost $1 million to date, including the leasing of the two buildings for nine months.
Tauranga Mayor Stuart Crosby said so far ratepayers had been taking the news well and were sometimes making jokes about old mould being found in the council.
He said the council was not expecting ratepayers to pick up the bill and it had money set aside for building maintenance and repairs as well as emergency funding.
"We're a big organisation, we have renewal funding. We're a two hundred million dollar a year business with three and a half billion dollars worth of assets. Until we get the actual figures we don't know, but we have options other than just putting the rates up."
Stuart Crosby said a report on the money spent on the cleanup so far was expected next week.
However, he said the real costs would come when repair work started on the buildings.