The Transport Minister's responded to criticism of a new long-term rail plan

The plan involves a huge investment, to more than double patronage on the Auckland metro network - and increase freight capacity, to take trucks off the road.

But the tucking industry and National are raising questions over the "dubious economic case" and the need to invest.

Phil Twyford says it's in the interest of New Zealand to go ahead with the plans.

He says if we don't invest in rail we'll never solve the congestion problem,or reduce the number of deaths on the roads or the emissions that cause climate change.