Scottish council leaders have warned that proposed reforms, described as the biggest shake-up of local government in 30 years, could fragment services instead of saving money.

The plans could reduce the number of councils from 32 to as few as six, prompting concerns about the “absurd” timetable and the possibility of dividing services.

Under the proposed two-tier system, larger regional bodies would oversee strategic services such as education and economic growth.

At the same time, about 120 to 160 community authorities would manage local matters including licensing and town-centre improvements.

The Scottish Government has not indicated the proposed authorities’ likely geographical boundaries or how they would be funded.

Fife Council leader Councillor David Ross said: “The proposals for local government reorganisation made by the First Minister are badly thought out and a recipe for confusion, as in reality, they will lead to fragmentation of services and a return to a silo mentality.

“It is unclear what the real objectives are, and much of the work on local governance and public service reform that has been going on for many months now seems to have been ignored.

“The division into regional and local is simplistic and ignores the complexities of Scotland’s local government landscape.”

Ross said councils already collaborate in several areas and argued it would be “much simpler and more effective” to retain the existing structure.

He suggested authorities could instead merge voluntarily and expand partnerships through city region and local growth deals.

He said: “Most local government services cannot simply be broken down into ‘community areas’ without losing economies of scale and operational efficiencies, and if the First Minister thinks the process will produce financial savings, he is sadly mistaken.

“The Scottish Government should commit to a properly organised independent review if they were serious about local government reform, as it would take the time needed to consider a full range of evidence and views, rather than rely on the half-baked proposals now on the table from the First Minister.”

However, the Scottish Government said the plan reflected concerns that councils had become too large to be genuinely local but remained too small to act strategically.

Ministers have described the proposals as a “starting point” for reform.

Deputy First Minister Jenny Gilruth told the BBC: “Existing local government responsibilities could also be extended, including enhanced roles in economic development and business support so that individual areas can reflect local strengths and ambitions.

“We need to ensure investment is focused on frontline delivery, with the right staff in the right roles to empower communities and deliver real improvements in public services.”

Other council leaders offered more cautious responses while agreeing that further discussion was needed.

Falkirk Council deputy leader Councillor Paul Garner said: “It is too early to assess the full implications, but we will take part in any discussions or consultations on local government reform.”

City of Edinburgh Council leader Councillor Jane Meagher said: “We have been calling for more devolved powers, so we welcome this, but it is unclear how the community authorities would work or be funded, and what this would mean for Edinburgh Council.

“The timescale for such consequential and far-reaching reforms does not allow for serious, considered discussions with the Scottish Government.

“Eleven weeks to decide the future of public services in this country is absurd.”