The Buller District Council has revealed Cr Martin Hill is not a New Zealand citizen and his position has been vacated.

A West Coast councillor who has been ditched from his job due to not being a New Zealand citizen says his employer is one of the country's most "gagged" councils.

Australian citizen Martin Hill's position was vacant immediately as of Thursday after it came "to [the Buller District] Council's attention" that he was not a New Zealand citizen, a council statement said.

"All candidates sign a declaration as part of the process to say they are a New Zealand citizen, but the act does not require this to be checked or verified so occasionally this does happen," the statement said.

JOANNA CARROLL/STUFF Buller Mayor Garry Howard said it was "regrettable".

Hill said in a statement that he "honestly believed" that Australian and New Zealand citizens had reciprocal rights.

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He apologised to ratepayers for being unable to continue to represent them.

"I did not resign from the position as I know that in a matter of weeks I could easy rectify my citizen status. However, the mayor and chief executive were very keen to escalate this situation," he said.

The council has said it would call a by-election and has 89 days to do so. Hill said he would not stand again.

Hill –who was elected to represent the Seddon ward last year – labelled his experience working for "one of the most 'gagged' councils in New Zealand" as "very frustrating".

"I believe there is too much information not being circulated to the public under the disguise of being 'commercially sensitive'," he said.

"During my time at council I dealt with regular formal complaints from the likes of Cr Emily Miazga about sharing information and for sharing my opinions through the media. In my opinion she does not understand that she works for the ratepayer, not the CEO or the mayor."

Hill said he wanted to continue to work on community issues like the ongoing erosion issues in the Buller region.

He also encouraged his replacement to be open to sharing opinions through the media, although they would be "strongly discouraged".

"Also please do everything you can to stop the unnecessary spending, which is sending our rates sky high," he said.

He pointed to the $25,000 spent on a women's Buller sports event that was organised "behind the scenes" and to his knowledge was "without any council consultation" as an example.

Under the Electoral Act 2001 all nominees standing for election must be New Zealand citizens. The Whangarei District Council last month declared a by-election for the same reason.

Buller Mayor Garry Howard said Hill's lack of citizenship was "regrettable".

"However, council must comply with the act and council's electoral officer has a duty to act to follow the legal process," he said.

"I have encouraged Martin to get his citizenship and to stand again. There is an expense to a by-election, but it is not legally possible to hold a position and await citizenship."

Howard said Hill told him he was not a New Zealand citizen on Tuesday.

"We were meeting on a number of points and it came up in discussion. [I'm a] bit shocked by that particular revelation because of the process that candidates go through in their initial nomination," he said.

Howard had not spoken with Hill since Tuesday, but imagined he was upset.

"He was pretty gutted. He is pretty passionate about his community and his area.

"He's got a good profile in the community and it's just regrettable to see such a situation, but council's hands are tied. If you're not a citizen you can't hold office."

Whangarei District councillor Jayne Golightly resigned in September after it was revealed she was not a New Zealand citizen. A by-election scheduled for December 7 would cost about $35,000.

Citizenship issues have plagued politicians across the ditch, where MPs – including deputy Prime Minister Barnaby Joyce – unknowingly had dual Australia-New Zealand citizenship, breaching Australia's constitution.

"[Hill's situation is] the reverse case of Barnaby Joyce," Howard said.

It was a "strange situation" that permanent residents could enrol to vote, but could not hold council office, he said.

"There does seem to be an anomaly there and I find it just unfortunate that people are struck out on such a criteria."