A report showing how to merge the region's five councils, known as the Hawke's Bay prosperity study, will take another six to eight weeks to complete, passing its original deadline by more than two months.
The report is being written by consultant Peter Winder, who was expected to deliver stage two of the study to the Hawke's Bay Regional Council at the end of last year.
Mr Winder reported to the regional council last week where he explained he'd not had time to complete the study because he had been asked to step in to work as a commissioner at the failed Kaipara District Council in Northland.
Regional council chairman Fenton Wilson said councillors were worried about the length of time it was taking to complete the $100,000 study.
"Mr Winder completed the first stage of the study, which said there could be between $5 million to $25 million in savings by changing governance structure.
"That's quite a broad range and so the second stage of Mr Winder's report was about providing more detail to quantify those savings.
"So he went away to scope that out. He then went missing in action for a few months and there was a fair bit of frustration over that.
"The government has grabbed him to work as a commissioner at Kaipara and that has taken a lot of his time. But we've said that's his problem, not ours. We've got to a stage where we need him to get on with the work straight away because it is critical to the work of the region."
Mr Wilson said there needed to be more accurate figures showing what each council spends and what all of the councils spend together, to determine the savings which may be achieved through the councils working as one.
Regional councillor Neil Kirton said he was disappointed Mr Winder's work at Kaipara had forced the Hawke's Bay study on to the back burner.
"What's more concerning is the lack of leadership from the region's mayors and CEOs who need to be brought kicking and screaming to advance anything to do with amalgamation or better governance systems."
Mr Kirton said he thought the regional council and Hastings District council would be the only ones worried about the lateness of Winder's report.
"Napier isn't showing any great desire and I would think Wairoa and CHB are hoping the whole thing will go away."
Napier Mayor Barbara Arnott said she would rather the report be completed comprehensively in time, than something written up in haste.
"There are so many issues from the first stage of the report that is difficult to substantiate in terms of what it really means for the economic development of Hawke's Bay," she said.
"So it's no surprise it's taking a bit longer."