Transport must form a big part of the 10-year investment plan in the State’s infrastructure, which will be announced in a few weeks, Taoiseach Leo Varadkar has said.

He told the Dáil on Wednesday the Government would be guided in many ways by the National Transport Authority’s greater Dublin area plan which ran up to 2035.

He said when he signed the order to connect the Luas lines, and he was told it would not be open until 2017, he felt he could be anywhere by that year.

“As it happens, I am here, but public transport is something I really believe in and something in which we will invest very heavily into the future,’’ he added.

Mr Varadkar said projects in the mix included expanded bus services, additional carriages for Irish Rail, the metro project and the new Luas lines.

He was replying to Social Democrats TD Catherine Murphy, who said there was a lack of capacity in public transport, despite a very significant traffic congestion problem.

“In the past week alone, a number of buses have been diverted to try to alleviate the traffic chaos that is fast becoming the hallmark of College Green,’’ she added.

“This was exacerbated by the introduction of the cross-city Luas.’’

Ms Murphy said Ireland was facing a really significant problem in 2021 because of fines for not adhering to climate commitments.

“Not alone will investment in public transport offset the fines, but it will also deliver a public transport system fit for a modern Ireland,’’ she added.

Ms Murphy said there was understandable anger over the disgraceful treatment of disabled people on public transport, particularly relating to the rail network.

“That a disabled person would have to give notice of four hours just to take a DART into town, for example, is not acceptable,’’ she said.

Mr Varadkar said a lot of the return to traffic congestion and gridlock in cities was related to the fact the economy had improved and people were working again.

The reality was, he said, during the “lost decade’’, the State did not have the money it needed to invest in public transport.