Cornwall County Council has defended a £30,000 leaflet drop to all Cornish homes explaining its proposals for a unitary authority.
The county council believes having unitary status would save money
Cornwall is among 16 councils nationally being considered by the government for unitary status.
North Cornwall District Council says the leaflets are biased and should not have been paid for with public funds.
Cornwall County Council says the leaflets are acceptable as they inform households about the plans.
The council is sending the leaflets to every household in the county this month, asking for people's comments.
Graham Facks Martin, chairman of North Cornwall District Council said: "The Audit Commission has told all local authorities that public funds should not be used to man publicity campaigns whose primary purpose is to hold a particular view on a question of policy.
"In our view there's no doubt at all that the leaflet put out by the county council is seeking to persuade people to say yes to one council for Cornwall."
The Standards Board for England watchdog said no ethical codes had been broken.
David Whalley, leader of Cornwall County Council, said: "This about informing every household about the proposals which have been submitted to government and government have said these proposals are appropriate for this area.
"Our legal team are convinced that this is information that we are providing for people in Cornwall."
Under Cornwall County Council's plans, the six district councils and the county council would be scrapped and replaced with one authority.
Calls to hold a referendum on the plans have been rejected because the county council says it would not be legal.
A final decision will be made by the government later in the summer.