The Dublin Port Tunnel (DPT) is expected to be open by March or April next year according to the Minister of State for Transport, Ivor Callely.
The Minister said that the tunnel should be open following the testing of the tunnels' operations and safety features adding that the experience gained will help on further infrastructure projects.
"The experience and what we have achieved here will give us the confidence and courage to pursue other such infrastructural tunneling projects to benefit this city, including the concepts of extending the DPT to the south, and commencement of a Metro system," Mr Callely said.
Mr Callely was speaking at the mouth of the tunnel today following a visit from the Taoiseach Bertie Ahern to inspect the tunnel works.
The final cost of the tunnel is estimated to be €751 million, €170 million more than the cost quoted at tender stage in 2000.
After his visit Mr Ahern called the tunnel 'magnificent' and dismissed the cost overruns as normal for a project of its scale.
"If you sit down with your pencil and try and work out what will happen and try and account for things like snails and archaeological digs and things you'll never do anything.
"I think we have to look ahead and I'm very proud of the people who have got on with it - yes we may have some overruns but we have modern infrastructure," the Taoiseach said.