Transport Minister Steven Joyce has welcomed progress on Auckland's Western Ring Route, with confirmation of the alignment the route will take.

The Board of the NZ Transport Agency this morning confirmed details of the combined surface / tunnel alignment, which has been the subject of public consultation since May.

Mr Joyce says confirmation of the plan will bring long-awaited certainty for Auckland and for the local community.

"This $1.4 billion project strikes a fair balance between the needs of the local community and those of the country and the economy.

In January the Minister asked officials to investigate alternative options for building the Waterview Connection after a business case prepared for the previous government released in December showed the total cost of the proposed twin tunnel option was $2.77 billion.

The Transport Agency found that the Waterview Connection could be built for considerably less and selected the $1.4 billion alignment.

"Given these numbers and the increased government commitment to state highway investment through the National Land Transport Fund, the project will be built using the fund. This means it won't be financed by borrowing, as envisaged by the previous government," says Mr Joyce.

"While this option is considerably less expensive than the $2.77 billion bored tunnel plan, it is still New Zealand's most expensive project by a considerably margin.

"Now that the proposed route has been confirmed by the agency, I look forward to the detailed planning and consenting process, before construction commences."

The proposed route includes building the motorway as a tunnel under Great North Road and in a second tunnel under the Avondale Heights. The resulting underground sections represent around 60% of the road's length.

The route chosen protects the Oakley Creek Reserve and the Phyllis Street Reserve.

Mr Joyce says the completion of the route, which has been identified as one of seven Roads of National Significance, is essential to the continued growth and economic development in the Auckland region.

"It will also contribute to better links for business and freight between key industrial hubs in the cities of Manukau, Auckland, Waitakere and North Shore."