First Minister Peter Robinson's DUP has today accused the North's Boundary Commission of gerrymandering in a fierce attack on its proposals to reduce the number of Westminster seats to 16.
Belfast would lose one seat - creating a proposed South East constituency leaving out the mainly unionist Dundonald and Braniel areas - and another would go west of the Bann.
Concern has also been expressed about the boundaries around the towns of Ballymena, Coleraine and Carrickfergus.
The commission rejected the DUP smear.
The DUP submission said: "Overall the commission's proposals have a disproportionately negative impact upon unionism. The effect permeates the proposals, leading to the conclusion that it is no accident."
Allowing Belfast to retain its four seats could produce a "ripple effect" which would disrupt the proposed boundaries in the north of Northern Ireland because Newtownabbey would have to be returned to Belfast.
Arguments around changes to the boundaries of the proposed three Belfast constituencies centre on whether Upper Braniel, nearby areas and Dundonald are included in Belfast South East or Strangford.
The DUP submission said the proposals were "atrocious".
"The term gerrymander is one that should not be quickly or lightly thrown about by anyone. However, in terms of the proposed South East Belfast the DUP feels that it can legitimately be used both in terms of the boundary with South West (Belfast) and Strangford."
The proposals would create three constituencies in Co Antrim - South Antrim, Mid Antrim and North Antrim - which would take Coleraine from East Derry. This would separate Ballymena from Antrim and place it in the same constituency as Larne.
The DUP said the proposals cut Ballymena and Coleraine from their natural hinterlands in a "brutal" division.
"The set of proposals produced for Northern Ireland are of no surprise to the DUP," it said.
"No satisfaction is drawn from the fulfilment of the DUP prophecy on this matter and the set of atrocious proposals produced."
East Derry DUP MP Gregory Campbell's constituency would be deprived of a large swathe of unionist voters if Coleraine is forfeited.
A spokesman for the commission rejected the claims.
"We conducted our business properly and thoroughly in accordance with the procedures laid down in the legislation and the outcome of elections is none of our business," he said.
One of its aims is to prevent local ties from being needlessly severed by boundary changes.
However parties are also looking to the Assembly elections and tight races for the final seat in many constituencies.
The North Belfast SDLP opposed the loss of one Belfast seat. Leader Alasdair McDonnell is MP for South Belfast, which would cease to exist.
"This will severely reduce the impact that Belfast, as the economic driver and the largest city in the north of Ireland has and goes against previous Boundary Commission recommendations which ensured that Belfast retain its four seats," its submission said.
The commission reviews parliamentary constituencies every five years.
On September 13 last year it published provisional proposals for its sixth review following a Westminster decision that the number of constituencies should fall. The 12-week public consultation included public hearings in Belfast, Omagh and Ballymena. They received 38 representations but very few people attended the meetings.
There will be a further four-week consultation ending on February 27 during which views are invited on comments and proposals received. Final proposals are expected by spring or early summer next year.
The commission delineated four western constituencies, Fermanagh and South Tyrone, a new Mid Tyrone taking in Mid-Ulster and West Tyrone, Glenshane and Foyle.
Proposed transfers of wards in areas like Broughshane, Portglenone and Carnlough near Ballymena sparked local concerns. Similar points were made about Crossgar, Loughbrickland, Killyleagh, Aghagallon and Magheralin. Whether Claudy and Bannagher should form part of Foyle or Glenshane is another problem which the commissioners face.
The consultation begins today.