The government is considering creating a new public agency to deliver Auckland's light rail project.
RNZ revealed last year that transport officials were warning that the major project was too big and too complex for any existing public agency to deliver.
They said expertise within an existing entity, like the New Zealand Transport Agency, would need to be bolstered or an entirely new agency would need to be created.
"The capability and capacity demands of a project of this scale and complexity are almost unprecedented in New Zealand, and no current entity has the necessary capabilities to deliver the project. All options will be considered, including building expertise within an existing entity or establishing a new one," the briefing stated.
The risks of the project's design and construction and who can best manage that risk will need to be considered when deciding who is best placed to deliver light rail, officials said.
"Given the complexity of the project and its significant funding requirements, we anticipate that there will need to be robust governance and assurance to manage Crown risk, including a detailed approach to change management and contingency management," they said.
Transport Minister Michael Wood said the government is currently considering that advice and what the best option is.
"As things stand, this is a very unique project so we don't necessarily have an agency right now that is kitted up and ready to go to deliver something of this complexity and scale.
"So whatever delivery we land on, whether it's an existing agency that's adapted or whether it's a new entity, we'll have to do considerable work to make sure it has all of the right tools that it needs to deliver this important project," Wood said.
The City Rail Link project in Auckland and the company established to deliver it (CRL) was a good example of the "kind of thinking we have to do".
"It's currently the biggest infrastructure project being delivered in New Zealand and that was a bespoke body that was set up to deliver it, taking account of those complexities, taking account of the need to have a relationship between the two sponsors, being the Crown and Auckland Council.
"We won't necessarily land on the same form as the CRL but it is an example of the kind of thinking we'll have to engage in to deliver something like light rail," he said.
The government is also considering the scope of the Auckland light rail project and its route.
Wood expects decisions on the project's future to be made by April.