More than €150 million has been spent on Dublin's MetroLink up to the end of last year even though no ‘significant’ physical work.

An estimate of the project - which would run from Swords, through Dublin Airport and into the city centre - puts the cost at around €9.5 billion.

However, the planning process alone will cost the State in the region of €300 million.

At the Public Accounts Committee today, Chair Brian Stanley described the cost of preparatory works as "astronomical".

“The projected cost of MetroLink, before the preparation work, would be in the region of €300 million,” he said.

“So, €300 million for MetroLink and we blew €150 million on MetroNorth.

“So, this will mean that we spent almost half a billion euros on the Metro before we even send a JCB out to the site.”

An artist's impression of Glasnevin MetroLink station. Image: MetroLink

National Transport Authority Deputy CEO Hugh Cregan said the expenditure is necessary because of the complexity and scope of the project.

“That is what it costs to bring a project of this scale through the design process and get it to construction,” he said.

“This is the time where you need to spend money in order to make sure that you’ve got the details right.”

An artist's impression of the Tara Street MetroLink station. Image: metrolink.ie

His colleague Garrett Doocey said such figures are typical for long-term projects.

“We should all acknowledge the cost associated with large multi-billion euro projects like MetroLink,” he said.

“To get them through the planning and pre-planning process is significant and will be significant.

“It’s our job, in terms of the Department and the NTA, to ensure that we’re getting value for money for that expenditure as it’s expended before we hit actual construction.

“We are assured, on a departmental level, that we are getting value for money.”

The underground rail system has faced significant delays over the past two decades but construction is due to begin next year.

If the project is completed on schedule, the first passengers should be able to travel on it in 2035.

Main image: An artist's impression of Seatown MetroLink station. Image: MetroLink