Kiama ratepayers will be left in limbo with council's efforts to permanently increase rates likely to fail.
Last year, Kiama Municipal Council took advantage of an offer from the Independent Pricing and Regulatory Tribunal to apply for an extra rate increase.
Due to what has now been tagged an "administrative error", council applied for a temporary rise, rather than a permanent one.
That gave council an extra 0.9 per cent rise, which it had planned to take off the new maximum rate figure of 5.2 per cent for the coming financial year.
Instead, councillors voted last week to write to IPART requesting that one-off rate rise become permanent.
But IPART said it won't be letting council do that, a spokesman saying it won't go back and change the "temporary" rate rise request.
"However, if Kiama Municipal Council considers that it requires additional general income to sustainably meet its operating needs, it may apply to IPART for a new special variation," the spokesman said.
"IPART will consider any request from Kiama Municipal Council in accordance with the legislative framework.
"When deciding any application, IPART is required to balance councils' need for financial sustainability with the impact of rate rises on ratepayers and their capacity to pay."
Before any new application can be made, councillors would have to vote in favour of it - and that can't happen until June 20, the date of the next meeting.
That's just 10 days before the new rate peg would be in force - nowhere near enough time to lodge an application and have it approved.