A study carried out for Auckland Transport Agency says the city should push forward with a rail link to Auckland airport.
The report is for Auckland Council, the Government and Auckland International Airport Ltd.
A rail link to Auckland airport is already on the council's 20 year wishlist.
The study says roads will not cope with growing numbers of airport travellers and freight over the next three decades and airport passengers will treble to 40 million per year inside that timeframe.
It recommends detailed plans and a full business case be prepared for a rail loop from Onehunga through the airport to Manukau.