Hawke's Bay Regional Council chairman Fenton Wilson is demanding fellow councillor Tom Belford formally declare his interest in a lobby group opposed to the Ruataniwha dam.
But Mr Belford says such a declaration would be inconsistent with the approach taken by other councillors and while he is sceptical about the Ruataniwha project, he remains open-minded ahead of a crucial vote next month that could seal the fate of the $275 million scheme.
Mr Belford is a founding member of Transparent Hawke's Bay, an advocacy group pushing "open processes, reliable information, and public involvement in councils' decision-making".
It lodged a submission opposing the irrigation scheme with the board of inquiry convened to assess resource consent issues related to the project and Mr Belford spoke to the group's submission in January during the board's hearing process.
When a conflict of interest register was circulated for updating at a meeting of the council on Wednesday, Mr Wilson challenged Mr Belford to record his involvement in Transparent Hawke's Bay.
Mr Belford declined, saying other councillors had not declared their involvement in community groups. "My declaration is accurate," he said.
Yesterday Mr Wilson repeated his call in an email to Mr Belford.
"If he's not prepared to register an interest he's either embarrassed or ashamed about the organisation or he's got other reasons which I don't know about," he told Hawke's Bay Today.
"But it's quite a simple request and he needs to think long and hard about why he wouldn't register that."
Mr Wilson pointed to guidelines published by the Office of the Auditor-General which told councillors they could "create a legal risk to the authority's [their council's] decision if you participate in the authority's consideration of a matter and you have made a formal submission to the authority in your personal capacity to support or oppose a particular proposal as part of a public submissions process".
The guidelines said councillors should "avoid making submissions on matters that will come before your authority for decision - doing so will usually compromise your ability to participate in the decision-making process".
Mr Belford said the written submission to the Ruataniwha board of inquiry was lodged in his name before he was elected as a regional councillor in October last year.
When he appeared before the board in January he made it clear he was doing so in a personal capacity, not as a councillor, he said.
"I have no problem with anybody knowing that Transparent Hawke's Bay is an organisation I belong to and if all it took to satisfy Fenton Wilson on that score was that I listed it on an interest sheet I'd be willing to do that if every other councillor was prepared to list every organisation they belonged to," he said.