Napier Mayor Bill Dalton has accused Prime Minister John Key of "a blatant lie" on amalgamation.
The mayor was reacting to Mr Key's Saturday radio comment on why Stuart Nash won the seat for Labour in the general election.
"There is discussion going on around amalgamation in Napier but that's got nothing to do with us," Mr Key told The Farming Show.
Mr Dalton later reacted via a blog on his website.
"In 2012, John Key's government removed the right of individual communities of interest to determine their own future governance model," he said.
"The Key Government put in place legislation that allowed numerically greater communities to force their will on smaller communities.
"In the case of Hawke's Bay, John Key's government said that the 72,000 people in Hastings should have exactly the same say in the future governance of Napier, as the 58,000 people in Napier do.
"Where's the fairness and sense of community in that?"
Mr Dalton said at least two of the three Local Government Commissioners hearing submissions on local government reorganisation "were well known pro-amalgamationists".
"And John Key tells us that the amalgamation debate has nothing to do with his government. Let me make it very clear. The current drive towards the amalgamation of local authorities in New Zealand is driven by the John Key Government. It is a plan straight out of central government and the plan totally ignores our communities of interest."
Auckland's local government reorganisation was a "disaster" and Auckland faced issues that did not apply to Hawke's Bay, such as urban sprawl.
"Why on earth would we swap our councils for Local Boards that have no power to rate or regulate? Local Boards that are useless and toothless and cannot make good decisions on behalf of their local communities. Local Boards that are totally financially controlled by a central council, where our local interests are in the minority."
A spokeswoman for the Prime Minister said Mr Key stood by his comment.
"As is stated in our Local Government policy, the government believes it is up to regions to decide the future of their local Government," she said. "We have changed the legislation to simplify the process for those councils that want to amalgamate but the decision to amalgamate is solely up to local people.
"The Government has no intention of imposing amalgamation on any specific region."
Local Government Minister Paula Bennett said the Government did not have an amalgamation agenda.
"We do have concerns about the sustainability of some regions, as does local government," she said.
"The people of Hawke's Bay will decide what the future of their local councils looks like."
Next year, Hawke's Bay has a referendum on the amalgamation of Wairoa, Napier, Hastings, Central Hawke's Bay and Regional councils into one organisation. Expected to be held in April, its wording is not yet released.
Mr Nash said Mr Dalton was correct - National was responsible for changing the law enabling larger councils to amalgamate with smaller ones, if the overall majority wished. Such forced amalgamation was "not democracy".
He predicted amalgamation would be narrowly defeated "which does not mean the status quo is ideal".