The biggest shake-up in Northern Ireland's local government for more than 30 years is due to be announced by Secretary of State Peter Hain.
The old power-sharing government at Stormont set up the review
The Review of Public Administration was set up by Stormont to examine the health, education and council services.
It is thought Mr Hain will announce a reduction in district councils from 26 to seven - Belfast and six others.
It will also see health and education boards replaced with what are seen as more streamlined structures.
Councillors in Northern Ireland are represented by the NI Local Government Association.
Its president, Peter Weir, said he supported change but that there should be 15 rather than seven councils.
"We believe that a seven-council model will be too remote," he said.
"It will mean that it will not be responsive enough to the needs of the electorate and we believe it will be a sectarian carve-up."
Nigel Smith from the Confederation of British Industry said he believed that, with the changes, councils would be more effective.
He envisaged fewer numbers of councils, councils with critical mass and, indeed, with additional powers.
"What we are expecting to see is a bigger investment in front-line services and, probably, more people employed there, but we are going to see cuts in the back office," he said.
It's understood the preferred option is to retain Belfast City Council
The public service trade union, Nipsa, has called for protection of jobs, pay and conditions of service for public service staff.
General secretary John Corey said: "The announcements will directly affect tens of thousands of public service staff and their families who will be extremely concerned about their futures.
"These men and women have delivered important public services to the whole community in Northern Ireland for the last three decades and more.
BBC NI's political editor Mark Devenport said it appeared that Belfast council would remain essentially the same.
"In the east, we will see the creation of three large and probably unionist dominated councils," he said.
These would be a greater Ballymena/Antrim type council, a greater Down council and a kind of suburban girdle around Belfast, taking in from Lisburn to Carrickfergus.
In the west, the councils would cover a similar, mainly nationalist population, but a much bigger territory in terms of geography, he said.
Mr Devenport envisaged a greater Derry council in north west, taking in Strabane, Limavady and down towards Magherafelt.
There would also be a council in the west, covering the area from Fermanagh to Cookstown and a southern council, covering the area from Craigavon towards Newry.
"We have yet to see precisely what the government will say about a requirement for power-sharing in councils," he said.
"Given that you would have largely unionist councils in the east, largely nationalist councils in west, clearly there will be concerns if the dominant groups on the councils simply ran them along their own lines without any kind of power-sharing," he said.
"The government, I believe, will say there will have to be some kind of safeguard to ensure cross community participation."
The review team which has drawn up the plans believes that ratepayers will notice the difference.
The team projects savings of £150m to £235m a year under the new regime, gains which, they say, will be made because of a reduction in duplication and bureaucracy.
However, Mr Devenport said that critics, who include all the main political parties except Sinn Fein, are not convinced.