The SDLP's Mark Durkan has joined other MPs at Westminster calling on the government to ensure that any decision on the replacement of the Trident nuclear weapons system is subject to a vote on the floor of the House of Commons.
The Foyle MP Mr Durkan said committing billions of pounds to nuclear weapons is "unjustifiable".
He said: "I am deeply concerned that the Chancellor of the Exchequer’s recent visit to the Faslane Naval Base in Scotland to announce £500 million of spending pre-empts a final decision on Trident replacement.
"I am therefore calling on the government to ensure that any decision on Trident replacement is subject to a vote in the Commons and to announce a timetable for that decision.
"I have consistently argued that cutting spending on Trident and other prestige follies would save billions of pounds at a time when public spending here in the North and in Britain is being severely hit.
"With such savage and indiscriminate cuts, the Treasury axe should first fall on fantasy status projects like Trident.
"Indeed, this money could be spent on other priority areas – not least children with special needs."
The Ministry of Defence (MoD) has said it will cost between £17.5bn to £23.4bn (2013-14 prices) to procure Trident's replacement system. The Campaign for Nuclear Disarmament estimate replacing Trident will cost £100bn.
The Ministry of Defence (MoD) has admitted that a Royal Navy submarine was responsible for damaging an Ardglass-based prawn trawler after towing it at speed through the Irish Sea.