The Corrections Department in Feilding filed the charge on February 2020. Berrett was to appear at Marton District Court to face the charge in March 2020.
Marton District Court said Berrett is now in custody on that charge.
Berrett's friend Nikki Pratt told Local Democracy Reporting and Open Justice that Berrett was arrested at her home in Rangataua in the Waimarino district on August 1 this year and had been held since then at Whanganui Prison.
His next appearance is September 15 in Marton. The maximum penalty for the charge is three months' imprisonment or a $1000 fine.
Berrett, 45, was convicted following a jury trial in May 2018 of threatening to destroy property, attempting to pervert the course of justice and two charges of blackmail.
He was sentenced in October 2018 to two years' intensive supervision and 180 hours' community work.
Evidence at his trial showed he threatened to burn down an RSA, blackmailed a NZ Defence Force artist and described attacking Parliament with explosives.
In 2012 Berrett approached the New Zealand RSA to sponsor a project for an Anzac memorial comprising two statues of soldiers saluting each other, one in New Zealand and the other in Australia. The RSA took up the concept, but problems arose when the RSA published a report giving credit for the initiative to Defence Force sculptor and painter Matthew Gauldie, who had supported the proposal.
Berrett has twice had appeals against the convictions dismissed by the Court of Appeal, the first in November 2019 and the second in February 2022.
Berrett is one of four contenders for the Rangitīkei mayoralty. The others are incumbent Andy Watson, Marton painter-decorator David Christison and Marton physiotherapist Simon Loudon.
Berrett's nomination for Rangitīkei mayor was received prior to August 2, when Rangitīkei District Council confirmed the nomination as complete. He was nominated by Janet and Murray Berrett.
In a handwritten letter to solicitors, a journalist and Pratt, emailed to the addressees on August 26 by a Whanganui Prison corrections officer, Berrett said he had no information relating to his detention.
"Since my arrest I have not appeared before a judge, I have had no legal counsel, I do not know what I am charged with, I do not know why I am being detained. I have not spoken with a lawyer, I received no information relating to my arrest.
"I am a mayoral candidate in this year's local body elections and my detainment is unlawful. It is undemocratic."
In a candidate statement no longer available on the council's website, Berrett said: "I seek change. I do not wish to lead. I wish to serve. This is the difference I offer. That is my motivation to stand for Mayor."
The council's deputy electoral officer Carol Gordon said candidate profiles are being checked by Electionz.com and should be available on the website next week.
Electoral officer Warwick Lampp said there were no restrictions on candidates with a criminal record standing for the local body election. There was nothing in law to prevent anyone with a criminal conviction from running for council or mayor, provided the sentence had been completed, he said.
Local Government New Zealand says in its guide for candidates that anyone currently serving a prison term of three years or more cannot stand. It said an elected member subsequently convicted of an offence punishable by imprisonment of two years or more would automatically lose office.
• Local Democracy Reporting and Open Justice are Public Interest Journalism programmes funded through NZ On Air
