But Environment Minister David Parker has said he will not use ''excessive regulating powers'' introduced by the previous government, although he will not comment further until he has received a report about Otago water issues.
In his mayoral report to Central Otago district councillors last week, Mr Cadogan said he was concerned about one of the possibilities of government intervention.
He reminded councillors of the government investigation into the Otago Regional Council's handling of water consents, and said they needed to be aware the minister could ''call in'' the coming plan change to set the minimum flow in the Manuherikia catchment.
If he did that, Mr Parker could then do one of two things: either send the matter straight to the Environment Court, or appoint a board of inquiry to decide the minimum flow, Mr Cadogan said.
Mr Cadogan said it ''could be argued'' the Environment Court option was reasonable, given the likelihood of a regional council decision on the Manuherikia minimum flow being appealed.
However, if a board of inquiry heard the matter, there would be no appeal rights.
''I think we can all agree that if a decision [on the Manuherikia minimum flow] is made in Wellington with no right of appeal, that would be completely unpalatable to the [Central Otago] community.''
Mr Cadogan said Mr Parker himself had argued against 2017 changes to the Resource Management Act that would give the Government greater powers.
At the time, Mr Parker called the amendments to the Act a ''deeply flawed piece of legislation'' and described the regulation-making powers ''that are conferred on ministers under this Bill as completely rebalancing the current division of powers between local government and central government in favour of the executive''.
When contacted for comment, Mr Parker said the ''excessive regulating powers'' previously conferred on the environment minister were being repealed in legislation soon to be introduced and he would ''not use those powers even before they are repealed''.
However, he said local authorities such as the Otago Regional Council had had ''three decades to sort this [renewal of water consents by 2021] out and haven't, which is why I have sought a report on the best way forward''.
Mr Parker said he would not comment until he had received that report.
He also pointed to sections of the Resource Management Act that said appeals on board of inquiry decisions were permitted only on questions of law.
