First Minister Peter Robinson's DUP has accused Northern Ireland'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 allegation of gerrymandering.
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 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. 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 such as 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.