Finance Minister Bill English has unveiled a National Infrastructure Plan that has identified the need for a second Auckland harbour crossing within the next 10 to 20 years. It did not detail immediately what form the crossing would take (either a bridge or tunnel) or how much it would cost.

"The existing Auckland Harbour Bridge is being strengthened to ensure it remains a strong, safe and viable link long into the future. However, building an additional harbour crossing is an important priority as the city grows, and it is a key component of the government's infrastructure plans for Auckland," the Plan said.

English said the first National Infrastructure Plan covered a 20 year horizon and had identified NZ$6 billion in government spending a year on physical assets, and that the government held NZ$110 billion worth of infrastructure assets. The plan provided a snapshot of public and private infrastructure, planned investment and the government's priorities.

"It gives infrastructure providers greater certainty about the Government's plans and ensures that planners and stakeholders have a clear sense of what is happening across a range of sectors," English said in a speech to the Trans Tasman Business Council.

I am reporting from this speech and will update with more details through the afternoon below.