"Many people work above and beyond what is reasonable to expect.
"Unfortunately there are two exceptions to this, Mayor Ellis and CEO Blair King.
"I have been subject to unacceptable behaviour from them which I consider bullying and abusive."
Mr Davidson said his ability to represent the community had been severely compromised as a result of the strained relationship and that the groups or projects he was associated with were at risk of being negatively impacted.
"I do apologise, to the people who elected and have supported me through the years, for not completing this term of council.
"I hope they understand I am resigning today because I am being prevented from effectively representing them."
Bush Telegraph reporter Dave Murdoch, who attended the meeting, said Mr Davidson's announcement did not appear to come as a surprise to the councillors and mayor.
"It happened right at the start, in the personal matters section," he said.
"He stood up, read the whole statement out.
"All the councillors shook his hand, wished him good luck, and he walked out."
Mr Davidson handed copies of his statement to the press bench.
"I think the councillors knew, they weren't shocked at all.
"They were ready to shake his hand. The mayor certainly knew."
Mr King would not comment on the resignation but said there would need to be a by-election within the year.
He said that the mayor had instructed that no comment was to be made by councillors.
Mr Ellis said he is very positive about the future of the Tararua District Council.
"These things happen and I think we have a strong council in terms of infrastructure and economic development," he said.
Of the seven councillors at the meeting, only David Roberts was able to be reached by Times-Age.
"There's not much I can say really," he said.
"He read out his resignation speech at the beginning of the meeting and then left.
"I don't know about the bullying, no, but if I did, I couldn't say.
"It was out of the blue and it's sad to see him go."
Following the meeting, Mr Davidson told the Times-Age he had told the mayor, CEO, and all councillors of his resignation over the past week, with the exception of Bill Keltie, who is on annual leave.
"Over the past 10 years I have been in council, and it has only been until reasonably recently for the terms that Blair King has been CEO that I have had difficulties.
"It has been a difficult but workable relationship - until recently."
Mr Davidson said he will still be involved in committees and groups in Eketahuna.
"At the moment I'm just going to have a breather and consider my options," he said. "I've talked with the community board and I am so grateful for the community's expression of sadness in my resignation today."
At the same meeting, Mr King was confirmed as chief executive for a further five years.
