Some of the Government's key motorway projects could take up to three years longer than expected, the Transport Agency has revealed.

That could push completion of the flagship "roads of national significance" programme to 2024, the agency has warned Transport Minister Gerry Brownlee.

It told the minister in February in a briefing document released to news organisations under the Official Information Act that it remained committed to "substantially completing" the seven roads by 2020-21, assuming funding availability.

"However, based on current levels and future revenue projections, this may be around 2023-24," the agency said.


A bar chart attached to the document appears to flag three-year delays in completing Auckland's $2 billion Waterview motorway projects, a new highway between Puhoi and Wellsford and the Waikato Expressway among others.

That is even though construction has begun on Waterview and three of the eight remaining sections of the expressway between Meremere and Cambridge.

Transport Agency chief executive Geoff Dangerfield said last night that the organisation still intended opening the expressway by 2019, but acknowledged there might be work to be completed after that, such as landscaping.

Agency spokesman Andy Knackstedt said the Waterview project, which includes new road tunnels from Owairaka to the Northwestern Motorway and a raised and widened traffic causeway to Te Atatu, was similarly on track for completion by the end of 2016.

Asked why the bar chart depicted a completion date of 2018-19, he said that was to account for remedial work such as revegetation.

But the agency has yet to confirm a start date for the $1.76 billion Puhoi to Wellsford highway, which is indicated in the bar chart as 2017 - three years later than earlier proposed.

Mr Dangerfield said dates for both sections, the first being from Puhoi to Warkworth, were "a function of available funding".

Of the overall programme, he said: "We are still committed to and working towards substantial completion by 2021, but depending on revenue, some may not be substantially complete until a year or two after that."

Mr Brownlee said of the briefing paper that it indicated the Government was "progressing a very aggressive infrastructure problem" but the agency had simply sounded a cautionary note about completion times.

"The Government's expectation is that NZTA [the agency] will expedite these projects as they have been requested and required to do, so I can't see at this point any reason why we would expect a slippage in the early part of the programme."

He said the Government remained keen on adding four more roads to the programme, although these were not planned at present.

But Green Party transport spokeswoman Julie Anne Genter said the Government would be wise to take expectations of higher oil prices far more seriously, and defer the roads "even further, because they are not good value for money".

"They're extremely expensive and we're in a tight situation where we need to spend our transport money as smartly as possible," she said.

"If we're going to spend billions on a transport project that is going to fundamentally transform Auckland and the economy and prevent us suffering from high fuel prices, it should be the [tunnelled] city rail link."

Ms Genter blamed a tight land transport revenue forecast on high fuel prices which were discouraging people from driving, hence reducing the Government's tax take.

* Roads of national significance - total cost
$9 billion-plus

* Auckland Western Ring Route (including Waterview Connection)
$2 billion-plus

* Puhoi to Wellsford
$1.76 billion

* Tauranga Eastern Corridor
$500 million

* Waikato Expressway
$2.4 billion

* Christchurch motorways
$730 million

* Wellington motorways including Transmission Gully
$1 billion-plus

* Victoria Park (done)
$400 million.