Auckland Council is making early moves on the plan for a downtown rail tunnel despite a cautious response from the Government.
The council's transport committee has unanimously endorsed a business case which says the tunnel would double the capacity of the rail network.
Committee chairperson Mike Lee says the Britomart rail terminus will reach capacity within the next few years without the tunnel.
Transport Minister Steven Joyce says some of the claimed economic benefits and forecasts of increased patronage need to be tested.
The committee is calling for a start to talks about how to fund the tunnel, securing its route and prepare for any planning consents.
