The NZ Transport agency spent almost $11 million on Wellington's $90 million Basin Reserve flyover before the project was shelved earlier this year.
An independent board of inquiry appointed to decide the fate of the flyover proposal declined the NZTA's applications for resource consent for the construction, operation and maintenance of State Highway 1 in Wellington between Paterson Street and Buckle Street/Taranaki Street in July in a majority three to one decision.
Among its reasons, the board said the agency had not given enough consideration to alternative options.
Figures now released to Radio New Zealand under the Official Information Act showed the NZTA spent $10.9 million on the project before it was shelved.
The figure included $3.4 million on Resource Management Act submissions, $2.3 million on legal fees and $2.8 million on staff attending the Board of Inquiry and 35 experts used by the NZTA to press its case.
NZTA's state highway manager Rod James told Radio New Zealand the figure was not out of the ordinary.
"It certainly is a lot of money, [but] it's certainly not out of context with other similar processes.
"In this region we've had three other boards of inquiry that have gone through in the past few years - Transmission Gully's one, MacKays Expressway, this one and the Peka Peka to Otaki section of the Kapiti Expressway - all of those have been similar kinds of ranges of costs.
"That's the kind of cost of going through a process like this."
The cost of staff attending the board of inquiry blew out after running 12 weeks longer than originally expected, Mr James said.
The agency had until Friday to appeal the decision, but had yet to confirm whether they will.
Wellington Central MP Grant Robertson told Radio New Zealand the $11 million had gone to waste.
"The NZTA didn't get those things right that the board of inquiry have highlighted, obviously money will always be spent in preparing a project like this, but ultimately all you have to do is listen to what the board of inquiry said to realise that money has definitely been wasted here."