But the council is now advising all its ratepayers the due date to pay their first 2023-24 instalment has been extended from October 20, to November 20.
Chief executive Darryl Lew said an inquiry into the extent of the problem was nearly finished.
By October 10, the council’s auditor had already identified problems for ratepayers within special rating districts.
This included Greymouth, where the rating base also pays a separate charge for the Greymouth floodwall.
Mr Lew last week said he was awaiting the update on the inquiry by PwC and he was reluctant to say yet how extensive the problem had been across the rating base.
"We’re closing in on it.
"We’re going to make a public statement in the next few days," he said.
On October 10, council officials admitted "a discrepancy" in the first instalment rates demands, which arrived in letter boxes early this month.
The problem was around the capital values used by the council to generate rates demands for individual ratepayers.
The council advised that for the special rating districts where the problem had been identified, ratepayers would be given more time to pay.
The council in June approved a general rates rise of 16.42% for 2023-24.
Instead, ratepayers were shocked to open rates early this month to find increases of anywhere up to 100% .
The percentage increase was compounded for special rating district areas, like the greater Greymouth town area, where alongside the 16.42% general rates increase, the Greymouth floodwall fees had also increased significantly in 2023-24.
The problem for Greymouth special rating district ratepayers was being further investigated.
The issue was initially thought to be in relation to the extension of the Greymouth floodwall rating district boundary and the capital value of property within this area, the council said in a statement.
A problem with the rates invoices for the Redjacks special rating district in the Grey Valley was also being checked.
While the review by PwC had found the rates invoices for Buller and Westland districts were correct overall, those covered by the special rating districts at Karamea, Punakaiki, Hokitika and Wanganui (Harihari) were incorrect.
Ratepayers identified in any of the special rating areas would receive a letter of explanation and an outline of what would happen next, the council said.
Ratepayers in areas identified with an issue, that had already paid their rates in full, would be contacted to work out a refund or remittance.
By Brendon McMahon
