The full extent of the black toxic mould that spread throughout Tauranga City Council offices will be revealed in the coming week, as staff shifts climb above 790.

A pair of independent reports are nearing completion some four months on from the outbreak of stachybotrys black mould in early December following complaints of sickness from staff.

Results from two independent reports on Tauranga City Council's mould outbreak are expected in the next 10 days. Photo: Bruce Barnard.

A full-scale investigation of the city's mouldy headquarters left large parts of the building and office space empty, with staff relocated to various points in the CBD.

Operation Clean project manager Terry Wynyard says since then, a final total of 798 shifts involving staff have taken place from areas that tested positive.

Large numbers of staff needed to be shifted twice - once to temporary safe areas such as Baycourt and council chambers and then into long-term leased accommodation in the downtown area.

He says the final shift came recently, with staff moved into the library building and parts of the civic building, while council chambers and a number of large meeting rooms remain operational.

A water tightness report from Prendos and a seismic strengthening report from Beca consultants are expected in the next week to 10 days, around March 20, says Terry.

The Beca report will then be peer reviewed before both reports, with recommendations sent to the council for consideration.

'It's more of wait and see for the current time,” says Terry.

'We have done everything we can and are just working through various processes that we have to work through.”

Terry says the Prendos investigation included an exterior examination of the civic building where dye-coloured water was pumped into anything that looked suspicious in order to see where water had emerged inside the building.

And as far as he knows the test went well, but the full results won't be revealed until the report is released.

Council plan to use this year's $1 million rates surplus to help fund unexpected costs.