Plans to scrap Dorset's nine councils to create two unitary authorities have won conditional government approval.
Secretary of State for Local Government Sajid Javid said he was "minded to" support the plan.
Six of the county's authorities voted to support the proposal but it was opposed by councillors in Christchurch, Purbeck and East Dorset.
The new structure, aimed at saving £108m over six years, would come into effect in April 2019.
Under the plans, all nine councils would cease to exist and Bournemouth, Poole and Christchurch would merge.
The second council would be formed from East Dorset, North Dorset, Purbeck, Weymouth & Portland and West Dorset.
The reorganisation was proposed after it emerged the authorities had to make £200m of savings by 2019.
An eight-week consultation held in 2016 found residents "overwhelmingly" supported the plans.
A joint statement from councillors in Dorset, Bournemouth, Poole, Weymouth, North Dorset and West Dorset said "the scale of the task cannot be underestimated" but it would be "far outweighed by the scale of the prize".
Christchurch council leader David Flagg said the authority intended to make representation to the Secretary of State.
David McIntosh, chief executive of Christchurch & East Dorset councils, said both authorities would consider making their own representations.
Leader of Purbeck District Council Gary Suttle said the authority remained opposed to the plan would "consider the implications for our residents and may make further representations during the consultation period".
Dorset County Council leader Rebecca Knox said: "We are delighted that at last we have clarity about the way forward for local government in Dorset."
She said the authority would now "explore new ways to deliver what the residents of Dorset will need in the future."
The change would likely lead to councillor roles being cut from 331 to about 180, and the loss of about 450 - mainly senior - council jobs.
Christchurch Borough Council had proposed a referendum in May but it was postponed for the general election.
Christchurch MP Chris Chope called the plan "an attack against democracy".
Two joint committees for the new council areas have already been set up to agree how assets are shared and how senior staff will be appointed.