The relationship between the twin cities' mayors has reached a new low, with Napier Mayor Bill Dalton accusing his Hastings counterpart of using "underhand methods and dishonest statements" to push a pro-amalgamation agenda.
Hastings Mayor Lawrence Yule has dismissed the claims, saying they are simply the latest in a string of personal attacks Mr Dalton has launched against him during the past six months.
The pair have been verbally sparring this week following the launch on Tuesday of a Hastings District Council marketing initiative to promote investment into the region.
Mr Dalton said the initiative - involving promotional videos and a slogan: "Great Things Grow Here" - was done in secret and would have been more effective if all the councils in the region had collaborated.
Mr Yule said while the slogan was kept confidential until this week's launch, the development of the videos was discussed during several months at meetings with the other councils, including Napier.
Mr Dalton launched a stinging attack against Mr Yule in a post on his blog yesterday.
In the post he accused Mr Yule of keeping the "Great Things Grow Here" initiative secret before its launch as part of a strategy "to show that the region won't work together".
Mr Yule is a supporter of plans to amalgamate the region's local authorities while Mr Dalton has been a vocal opponent of a draft amalgamation proposal for the region put forward by the Local Government Commission.
"[Mr Yule] is determined to try and show that amalgamation is the only way forward. And he has resorted to underhand methods and dishonest statements to support his case," Mr Dalton said in his post.
Mr Yule said he did not intend to respond to the post, which was the latest in a number of posts criticising him over the past six months. "I'm just getting on and doing my job. We differ in our view of the world and some ideas.
"It's a battle of ideas, it's not a battle of people and I'm not about to get into personal politics," he said.
"I think it's an unfortunate side of the amalgamation debate and a style of politics. We have different views on it. I will promote my views and ultimately the people will decide whether they like the system we've got or something different."
In the post, Mr Dalton said all leaders in the region were committed to working collaboratively except Mr Yule.
"He is determined to create division wherever possible to further his own political aspirations."
Mr Yule denied Mr Dalton's claim that the Hastings council's marketing initiative was an attempt to promote his own pro-amalgamation agenda.
"I completely reject that. This was simply us trying to respond to a need in the market when we didn't have some material so we tried to make it as open and inclusive as we could be so others could use it," he said.
"Preparing this video has absolutely nothing to do with any push for amalgamation. It was simply to help businesses in the region, to get more jobs and to help us market ourselves in getting those businesses."
He said the video promotion concepts have been very well received with a lot of organisations asking to add their content to it. The videos had been formated so individual councils or organisations could add to the content in order to meet their own targeting requirements, he said.
"We've been working on this for some time. We tried to make it available in a form anybody can use and I stand by that."