A CONTROVERSIAL €1m 'tunnel' to connect Leinster House to another nearby office block will pay for itself within two years, the Houses of the Oireachtas said.

The connection, which will join Leinster House and the state-owned Agriculture House office block, could save up to €700,000 each year.

The Houses of the Oireachtas said the move, which will see staff vacating expensive rented office space around Kildare Street, will end up proving far cheaper in the long run.

The Department of Agriculture is currently moving out of its headquarters building near the Dáil as part of its decentralisation to Portlaoise, Co Laois.

Already, at least two floors of the building are vacant and it is planned to move staff from other rented buildings into the empty space.

The new access route, which will involve a cut-and-cover style tunnel between the two buildings, will also make the whole complex easier to access for people with disabilities.

The Houses of the Oireachtas said work on the tunnel would begin this summer as part of a programme of works to improve Leinster House and its access.

The new access way will also end the practice of carrying important files and documents along Kildare Street without security.

A spokesman said: "The works currently being carried out are part of the continuing conservation of Leinster House as a national heritage building and follow a recommendation from the Office of Public Works.

"The works will greatly enhance universal access through Leinster House, particularly improving wheelchair and disability access within the complex."