The loss of building consent accreditation has cost the Christchurch City Council close to 10 million dollars.

International Accreditation New Zealand has announced the council has regained accreditation after assessment of its new processes.

It was stripped of it 18 months ago, over concerns about slow processing - prompting the government to install a Crown manager to run the council's building department.

Mayor Lianne Dalziel says it's cost the council in more ways than one.

She says an extra 10 million dollars was needed in the budget, but the loss of confidence was also expensive.