Transmission Gully's builder has been accused of giving Greater Wellington Regional Council "the run around" over 224 outstanding resource consent tasks.
The new $1.25 billion motorway out of Wellington opened in March this year after several delays.
It was down to the wire and only possible after some quality assurancetests and resource consent tasks were deferred.
This meant issues which weren't critical to road opening could be completed after the fact, allowing people to drive on Transmission Gully sooner rather than later.
But information in a regional council Environment Committee agenda reveals frustration behind the scenes.
An update on Transmission Gully said the extent of works required to complete construction and how long that was likely to take remained unclear.
There were a significant number of outstanding compliance and consenting tasks on the project, the update said.
"Greater Wellington has recently communicated to Waka Kotahi NZ Transport Agency our expectations of the agency as consent holder to demonstrate greater ownership and leadership in closing out compliance and approvals requirements, and reiterated Greater Wellington's role as regulator."
Transmission Gully has been built through a public-private partnership (PPP), the Wellington Gateway Partnership (WGP), with CPB Contractors and HEB Construction subcontracted to carry out the design and construction.
Council chairman Daran Ponter told the Herald council officials were being given "the run around" by the builder.
Ponter said officials had shown significant flexibility with deferring some of the consent tasks.
"Having done that, we want the road constructor and Waka Kotahi to hold up their end of the bargain by delivering the things they should have before the road opened."
He said while people could drive on the road, the project was not complete.
"The constructor needs to tie off all of those loose ends."
HEB and CIMIC, which is CPB's Australian parent company, both declined to comment.
Waka Kotahi transport services general manager Brett Gliddon said there were 224 consent tasks remaining for Transmission Gully.
He said 221 of these were the responsibility of WGP and their major subcontractor, CPB HEB.
"These tasks cover a range of matters, including monitoring and reporting, fill sites, planting, perched culverts and stream works, decommissioning of sediment retention ponds, temporary erosion and sediment control devices and temporary earthworks."
Gliddon said additional resource consents were also required to complete some works, so the number of outstanding tasks has and is expected to increase.
Waka Kotahi was working closely with WGP and CPB HEB on the remaining construction works and to deliver the intended environmental outcomes, Gliddon said.
He said the transport agency was also working with the council on technical matters to get the remaining consenting tasks resolved.
Council environment management general manager Al Cross said officials were waiting for Waka Kotahi, the consent holder, to provide the information needed to approve and close out the majority of these tasks.
"While Greater Wellington has a broad understanding of what these tasks and requirements could be, we are still waiting for a detailed programme of works from Waka Kotahi."