Work is split up as:
Contract 1 (£650,00) – Northern Area – Ballymena/Larne, Antrim, Ballymoney/Moyle, Coleraine, Londonderry and Limavady
Contract 2 (£800,000) – Southern Area – Banbridge, Craigavon, Armagh, Ards, Down and Newry/Mourne
Contract 3 (£700,000) – Eastern Area – Belfast (north and south), Castlereagh, North Down, Lisburn and Newtownabbey/Carrickfergus
Contract 4 (£100,000) – Western Area – Fermanagh, Omagh, Strabane, Magherfelt, Dungannon and Cookstown
The duration of the works is for a one year period, with the possibility of extension to a maximum of four years.
Tenders are due in on 6 October.