Auckland Council says its mistake in calculating rates owed by activist Penny Bright was a one-off, and does not indicate a wider issue.
The council's chief financial officer Kevin Ramsay said its error did not change the fact that Ms Bright "owes thousands of dollars in unpaid rates bills".
"A number of options remain open to Ms Bright to settle this without further need for court action and delay," he said.
Yesterday, a judgment allowing the forced sale of Ms Bright's Kingsland home to pay the debt was set aside in Auckland District Court after errors in the council's calculation was highlighted.
"The errors the court referred to relate almost entirely to the incorrect inclusion in Ms Bright's rates bill of previous orders of court costs against her which remain unpaid but were separate from the rates owing," Mr Ramsay said.
"Auckland Council regrets that errors were made, and notes they are confined to this particular court case and are not indicative of any widespread issue.
"The court has allowed Auckland council to amend its application to correct those errors and this will be done in the near future. The court commented that Ms Bright did not appear to have any grounds for not paying her rates."
In court, Auckland Council lawyer James Hassall blamed an "over-zealous" council worker for including the amounts on the rates summary.
Judge Harvey said the amounts made up "almost half the claim" on the document.
Ms Bright claimed it "proves this rates statement is fundamentally flawed".
Judge Harvey said he had no choice but to set aside the judgement, as the "basis of the claim is inaccurate", describing it as a "fundamental problem".
However, he warned Ms Bright: "You may have won this particularly battle, but the war is not over."
Ms Bright let out a quiet "yippee" in court after the decision was made.
Speaking outside court, a jubilant Ms Bright said: "It proves again that ordinary people can do extraordinary things, and that you can take on city hall and win.
"It goes to prove the importance of when you're right, don't back down - faint heart never won fair go."
The veteran activist has refused to pay rates on her Kingsland home, which had a 2011 valuation of $530,000, until the council publishes details of its deals with private contractors in a prominent position on its website.