The Government is to invest more than €200 million in a long-awaited major road in Co Mayo, Taoiseach Leo Varadkar has confirmed.

Mr Varadkar, along with Minister for Rural and Community Development Michael Ring and Minister for Transport Shane Ross will on Tuesday afternoon formally announce the development of the road from Turlough, outside Castlebar, to Westport.

The Cabinet signed off on the project on Tuesday morning.

Labour transport spokesman Senator Kevin Humphreys said the N5 road project would cost €241 million, €71 million more than was quoted at the start of the year when the figure of €170 million was given.

He questioned whether other projects would be delayed as a result of the reported over-run.

“That’s an increase of more than 40 per cent,” he said. “”I want know what has happened in the past 10 months to cause costs to spiral by €70m - and importantly, will any other planned projects be delayed as a result?”

Mr Varadkar confirmed Cabinet approval of the project in the Dáil when responding to Sinn Féin TD Louise O’Reilly

She said Irish road infrastructure compared poorly with the most advanced European countries, and pointed out that the programme for government committed to increased capital investment for the northern commuter line which was operating at capacity.

The Dublin Fingal TD said it was no use telling people to alter the times they come to work, in reference to attempts to encourage commuters to take trains at less busy times. Additional capacity was needed now, she said.

Mr Varadkar said Ireland “is a very young country with an expanding population and we’ve only been wealthy for the past 20 or 30 years”, so Ireland was well behind other countries.

London and Paris were building metros over 100 years ago but Ireland was only now starting to do that.

He added that while €200 million would be invested in the Castlebar to Westport road, the new expansion of the Luas line was well under way and the first extended carriages were arriving.

He said that would result in an additional 30 per cent of capacity on the green line.

The Taoiseach also said that additional carriages had been ordered for the northern and Maynooth lines, which take four years to arrive.

A further €100 million was being spent on the National Train Control Centre which would provide for more train slots and more capacity on the commuter lines.