Mr Little yesterday denied the claim that he had been maligning Mr Joblin.
"Unfortunately I've had to put up with a lot of stuff being chucked at me in the last two or three months but that's just part of being the mayor, I don't go on the attack," Mr Little said.
Mr Joblin said in his email: "I was voted on to council by people who trusted in my experience and judgment, but to continue to remain on council now would serve only to further compromise my own principles. I believe I can now be more effective as a ratepayer advocate from outside of council."
In September he was one of four councillors who voted at an extraordinary meeting to halt more than $1 million of spending on several council projects, initiatives and staff appointments.
The spending cuts, including removing funding for a just-appointed Maori relationship manager, were partially reversed later in the month after legal advice that councillors could potential be held personally liability for the consequences if the decision was not revoked.
Law firm Simpson Grierson warned the council its actions had put it at risk of being sacked by the Local Government Minister who has the power to replace dysfunctional local authorities with commissioners.
Mr Power angered councillors by writing in a council report that the four who voted to stop the spending had undertaken "various unlawful and improper acts".
Mr Little said he had no concerns about Mr Power's management of the council and was supportive of the vision he had for the organisation.
"I just think any new CEO seems to get criticised. It astounds me that people slag people off in public. We're meant to be a good employer and when you're slagging the CEO you're not being a good employer."
Mr Joblin is a member of pro-amalgamation group A Better Hawke's Bay and has been a lone voice in favour of the move to merge Hawke's Bay's five local authorities on what is otherwise a strongly anti-amalgamation council.
Mr Joblin - Wairoa's second highest-polling candidate, behind Mr Little, in last year's local body elections - said yesterday his resignation would allow him to speak out more forcefully in favour of amalgamation and about his concerns about the council's direction.
Nominations for the vacant council seat open on Monday and close on December 22. Voting papers will be delivered in late January and residents will have until February 17, to vote.