More than two thirds of Auckland's $58.9 million light rail spend has been on consultants, Newstalk ZB can reveal.
The Transport Minister's office has defended the spend and a spokesman said projects of this scale required significant planning, investigation, and design before spades hit the ground.
But National's transport spokesman Simeon Brown said the project was going nowhere.
"Labour promised to build light rail from Auckland's CBD to Mt Roskill by 2021, but all they have delivered is millions of dollars worth of reports."
Brown accused the Government of being all talk and no action on its promises, while Aucklanders were stuck in congestion.
In the past five years the Government has spent $58.9 million on the Auckland light rail project and $41.5 million of that has been on consultants, as of early June.
The figures were revealed following written parliamentary questions by Brown.
"The nature of the work of consultants is essential to the strategic approach to rapid transit in Auckland, which I note the Member himself supports", Transport Minister Michael Wood said in response to one of the questions.
A spokesman for Wood's office added successive governments have failed to future-proof Auckland with a proper linked-up rapid transit system.
"Of course a city-shaping investment like this requires a significant investment, but it is an asset that will serve Auckland for generations, and the costs of doing nothing are higher."
Congestion alone costed the Auckland economy about $1.3 billion a year pre-Covid-19, the spokesman said.
In late January, Finance Minister Grant Robertson and Transport Minister Michael Wood unveiled the Government's preferred option for light rail - a hybrid system running in tunnels from Wynyard Quarter to Mt Roskill and then proceeding at street level to the airport.
The ministers said the "hybrid" system had been chosen over two other options: light rail at street level costing $9b and light metro above or below ground costing $16.3b. This was because it had greater carrying capacity, was less disruptive and better aligned to a linked-up rapid transit transport network, they said.
The ministers said the new line would be designed, consented and built by the early 2030s at a cost of $14.6b.
But Treasury papers released in March said the project could cost up to $29.2 billion.
Information provided to Treasury by the Light Rail Establishment Unit noted cost estimates with an accuracy range of -50 per cent to 100 per cent based on a "very low level of design".
This meant the costs for the Government's option "could range between $7.3b and $29.2b".