Options for achieving that will be the subject of a report to councillors at the end of this year.
While councillors earlier this year asked staff to investigate how it could get the project done sooner with no or minimal increase in rates, a recent report to councillors on transport project priorities for the next 10 years suggests staff are working on a time frame of having the work done within four years.
It had been scheduled to take another nine years to finish.
Transportation group manager Gene Ollerenshaw confirmed staff were exploring, as instructed by the council, how they could remodel the long-term budget to allow for the Broad Bay-Portobello and Vauxhall-Glenfalloch sections of the project to be done at the same time, or as close as possible, and have the remaining sections done in a shorter time frame.
The work follows a high level of community interest and debate over the sequencing of the project, including 578 submissions made on this year's annual plan.
Using a small surplus in the funding from the New Zealand Transport Agency was one of the options being explored, he said.