The Department of Transport and the National Roads Authority (NRA) are finalising details of a 10-year, road-building programme which will cost between €15 billion and €20 billion.
The proposals, which will include a dual-carriageway linking Limerick to Sligo, will be brought by the Minister for Transport, Mr Cullen, to the Cabinet sub-committee on transport next month.
A feasibility study into a Dublin outer ring road will also be included in the package.
Proposals for an eastern by-pass of Dublin, which would run under Dublin Bay and along Sandymount strand, are also to be re-examined. A decision is not expected on the road in the near future, and the huge costs and environmental issues of such a plan make it a very long-term prospect.
The road would begin at Dublin port, passing under Dublin Bay and along Sandymount Strand, linking up with the M50 and N11 south of Dún Laoghaire.
The Government's 10-year plan will also include the current five-year, €8 billion road- building programme which will see dual-carriageway and motorway roads linking Dublin to Galway, Waterford, Cork and Limerick.
Yesterday Mr Cullen announced details of the Government spending of €1.45 billion on this programme in 2005.
This year will see the completion of 40 kilometres of new roadway, including the Dublin Port Tunnel and the final link of the M50 motorway, the Minister said.
Nineteen new projects are also to begin this year, including the Waterford by-pass and the controversial M3 through the Tara/Skryne valley.
According to figures published yesterday, €40.4 million will be spent on road-safety measures.
"The scale of the work and spend for 2005 outlined today demonstrates how far we have come in such a short timeframe," Mr Cullen said."This year alone we are providing €1.45 billion, compared with €294 million in 1997."
He refused to be drawn on the details of his transport plan, which he would be presenting to Government colleagues next month. "A lot of very good projects have been put forward," he said, referring to proposals for a metro line to Swords and an underground interconnector linking Heuston station to Grafton Street and the docklands.
He said new roads would not be the solution to transport problems, and new public transport infrastructure would be a key to this. However, he would not indicate which projects he favoured.
Meanwhile, construction has begun on the first "two-plus-one" road. These consist of three lanes, with the middle one acting as an overtaking lane. The first of these roads is under construction between Mallow and Rathduff in Co Cork.