Taupo's mayor wants the Serious Fraud Office to come clean with details about why it is investigating the district council.
A spokesperson for the SFO said on Tuesday it is investigating the council following a complaint but can't provide any information about the specific matters being investigated.
Mayor Rick Cooper said he is furious the SFO has put a gagging order on the council's chief executive Rob Williams and a $5000 fine if he talks.
Mr Cooper told Radio New Zealand's Checkpoint programme on Tuesday he doesn't know what department is being investigated, or how long it will take.
"These usually take four to five months. Well, guess what happens on October 5 in five months time - we have an election. Now I think we should start joining some dots together. I'll be watching very carefully whose name goes in the runners' box - that's for sure."
Mr Cooper said he is conducing his own internal investigation.