A $300 million Budget boost for land transport is expected to pay for about 7km of road - roughly the cost of the proposed new stretch of motorway from Albany to Puhoi.
A leading roading lobby group yesterday criticised the announcement, saying it would do little to speed up the "glacial pace" of New Zealand's infrastructure development.
Stephen Selwood, chief executive of the Council for Infrastructure Development, said the money would not result in any major new projects being started or completed.
The increase will come in three $100 million instalments from next year.
Transport Minister Pete Hodgson said it would raise the amount in the National Land Transport Fund to more than $8.4 billion over the next four years.
The strength of the economy meant the increases could be made without taking money away from other areas.
"This Government is building up the nation's vital infrastructure and wiping out a legacy of neglect," Mr Hodgson said.
But Mr Selwood said the money would only enable treading water.
Before the Budget announcements, increased costs had put in jeopardy a number of projects due to start before 2008, he said.
These included safety improvements and passing lanes at the State Highway 2 blackspot at Mangatawhiri, and the extra cash would mean these could go ahead.
"But major new roads like Auckland's Western Ring route, the Waikato Expressway, and an additional Auckland harbour crossing still remain well beyond the 10-year horizon and public transport initiatives will still be constrained by lack of funding," Mr Selwood said.
Exactly where the money will go, and how it will be prioritised, will not be known until the National Transport Plan is released in July.
Mr Hodgson said Government spending on transport was now 50 per cent more than it was in 1999.
But Mr Selwood said New Zealand's investment moved at a glacial pace compared with other countries.
Sydney's $2 billion M7 Westlink project and Melbourne's $4 billion Connect East project were being delivered through public-private partnerships within five years, from start to finish.
"Public-private partnerships empower the industry to get on with things and take responsibility if it does not, and that's what almost every major country does," Mr Selwood said.
New Zealand needed that kind of "paradigm shift" to secure its social and economic development.
His group had hoped for a clear signal of the Government's commitment to long-term capital investment to address the country's inadequate infrastructure, but this had not happened.