Auckland mayor Len Brown's being accused of ignoring planning processes and abusing the task of sorting out a fair rates system for the super city.
A rates review in 2007 recommended the differential paid by commercial properties be removed.
Instead, business will pay the same proportion of rates as under the combined legacy councils, and that rates differential will reduce over the next decade.
Chamber of Commerce head Michael Barnett says the decision was made 24 hours after businesses made some complicated but good ideas for change.
"There cannot have been any work done on those ideas, and the Mayor is saying that we're going to have the same proportion of rates collected in the same way they always have been. It's appalling."
Mr Barnett says while some businesses will find their rates will drop - others will pay increases of up to 45 per cent.
Photo: Len Brown (NZ Herald)