The North's First and Deputy First Ministers, Mr David Trimble and Mr Seamus Mallon, have accused the two DUP Ministers of "ducking their responsibilities" by refusing to co-operate fully with Executive colleagues.
Mr Mallon said the Regional Development Minister, Mr Gregory Campbell and his party colleague, Social Development Minister Mr Maurice Morrow, were arguing purely for their own Departments' needs rather than looking at the wider picture.
The call came as the Railways Task Force, set up in April to examine options for the future of the North's railway network, delivered its interim report to Mr Campbell, whose Regional Development Department is in charge of railways.
In its report, the task force outlined three main options for the future of the North's rail service, including the closure of the network with the exception of the Dublin-Belfast line at an estimated cost of £9 million sterling over the next three years. Another option would be a consolidation of the existing network with emphasis on the main commuter routes from Belfast to Bangor, Larne, Ballymena and Lisburn costing around £105 million. Upgrading the entire network at £175 million is also suggested as an option.