Auckland Council is waiting for the government to sign off on plans to reallocate $874 million originally earmarked for the Mill Rd project and Drury as part of the NZ Upgrade Programme.
But Auckland deputy mayor Bill Cashmore said the lack of certainty over the projects and where and when the money would be spent was an ongoing source of frustration.
Depending on what the government decided to do with Mill Rd could impact the council's own spending plans if it had to pay for additional roading and infrastructure, he said.
And he said it could also have major ramifications for both the council and Auckland Transport's finances.
"We need the green light from the government on where that funding is going to go," he said.
"The lack of certainty over this is really frustrating.
"It could delay what we can deliver. But at the moment we just don't know."
The $12 billion NZ Upgrade Programme was announced in 2020 and included funding to upgrade rail, roads, schools and hospitals across the country.
But the Mill Rd project, which was included as part of the package, was thrown into doubt in 2021 after the government said it was scaling back its plans for the works.
In June 2021, Minister of Transport Michael Wood confirmed the estimated cost of the project had grown from $1.35b to $3.5b due to soaring property prices and the land purchases needed for it to go ahead.
As a result, the government would focus on targeted safety upgrades to the northern section of Mill Rd and walkways, cycleways and public transport in the wider Drury area, he said.
In a statement, a Waka Kotahi NZ Transport Agency spokesperson said work on a business case for the New Zealand Upgrade Programme's South Auckland package, including the Mill Rd and Drury upgrades, was well under way.
"Waka Kotahi expects to submit the business case to Ministers Wood and Robertson for approval in the coming months."
The spokesperson said because the programme was funded directly by the government, the relevant ministers chose which projects were funded and their scope.
"It is the ministers who will then decide on the package and how the $874m will be allocated."
National Party transport spokesperson Simeon Brown said the longer the government put off making a decision on Mill Rd and Drury, the higher the costs would be for construction and any land purchases required.
Brown said the council needed some certainty as well.
"Ultimately the minister of transport needs to make a decision on this," he said.
"The council will want to know what connecting roads might need to be upgraded and how much funding it will have to invest."
A spokesperson for Wood said a business case was in the works and he expected to receive advice on the South Auckland package in the next few months.
Local Democracy Reporting is Public Interest Journalism funded through NZ On Air