A building boom including construction of the City Rail Link (in red) is about to start in downtown Auckland.

Aucklanders coming into the city for work or play are about to be sent a very strong message - leave your cars at home.

From next month, downtown Auckland will become a construction site, as major projects including the City Rail Link (CRL), the International Convention Centre and numerous office and apartment towers get underway.

The three-to-five year building boom will create traffic chaos, and city officials' plans for grappling with it include an extended publicity campaign telling Aucklanders to get out of their cars or face gridlock.

Auckland Transport Auckland Transport is creating 2km of 24-hour bus lanes in the CBD (in green) to help keep the city moving.

"We are targeting a modal shift… and that is onto active transport, which is your walking and cycling, and obviously public transport." CRL construction manager Chris Bird said.

Albert St and Victoria St West in particular will become almost no-go zones, and travel from east to west across the CBD in general will be slow.

In November Auckland Transport begins construction of a new stormwater pipe up the length of Albert St to make way for the CRL.

From May next year it starts building the "cut-and-cover" CRL tunnels, reducing the street to a narrow access-only lane on each side.

At various times the Victoria St intersection will also be reduced to one lane as two shafts for the CRL are constructed.

Meanwhile, other big projects will begin in the area.

Casino operator SkyCity has vowed to start building the long-awaited International Convention Centre between Hobson and Nelson Streets by the end of the year.

A 30-storey office, hotel and retail tower on the old New Zealand Herald site in Albert St gets underway before Christmas.

It escalates from there, with projects such as the Park Hyatt Hotel on the waterfront, the 36-level Downtown centre and the 52-storey NDG Tower on Albert St all starting in 2016.

People would still be able to walk everywhere and access to building carparks would be maintained, CRL communications manager Carol Greensmith said.

Motorists could still drive down routes such as Albert St if they needed to. "I'd choose not to, if you've got a brain." she said.

As part of its strategy to keep the city moving Auckland Transport (AT) is moving and upgrading bus routes and introducing 24-hour, 7-day bus lanes in parts of the CBD.

The two-stage project running until the CRL tunnelling starts in May will be accompanied by a significant publicity campaign, including ambassadors at bus stops, text messages to HOP card users, and an AT roadshow touring the foyers of central city office towers.

A video campaign urging downtown commuters to "break off" their relationship with their cars will be part of that.

Communication about what was happening couldn't come soon enough, said Kate Healy, chair of the council's independent City Centre Advisory Board.

"If I was working in Albert St, for example, I'd be very concerned about the lack of information.

"I would know that this is sort of coming but I wouldn't know exactly how it was going to impact on me," she said.

The City Centre Advisory Board had "certainly been having conversations" with council officials about what plans they had in place and how they were going to communicate them.

"Because when you have a vacuum of information you create a whole bunch of panics that may or may not be called for," Healy said.

The first phase of bus shifts begins on October 18, with a number of bus routes moved out of the works area. By May no buses will run down Albert St.

Phase two focuses on moving buses away from Lower Queen St and Customs St.

Demolition of the Downtown shopping centre to make way for a new office and retail development begins on May 20.

By November next year the front access to the Britomart train station on Lower Queen St will be closed, and a temporary access and services block will be built at the back.

The bus changes are also part of AT's New Network project, aimed at making public transport routes easier and faster.

It involves "turn up and go" bus services from 7am to 7pm on major routes, with smaller hub services feeding into them and the journey charged as one trip on the passenger's HOP card.

The changes were going to happen anyway and had been brought forward to coincide with the start of the CRL works, Greensmith said.

"So if we move people we move them once, we move them permanently, and that will be their new world going forward."

Improvements to the bus service to encourage people to give it a go would be a key part of reducing private vehicle traffic, she said.

AT had done a lot of modelling to see what would would happen to traffic flows during the works, Chris Bird said.

"It predominantly does show some disruption, particularly on east-west routes.

"There will be delays on Victoria St, in the order of two to three minutes."

It would be monitored constantly using real time data, and the agency had "some things up our sleeve" if it got too bad.

"We have some pretty stringent conditions which stipulate no more than a few minutes on specific routes, and we're not allowed to break them," Bird said.

BIG PROJECTS ABOUT TO START:

- November: City Rail Link, from Britomart to Mt Eden - November

- 164 apartments and two commercial buildings, Wynyard Quarter - Oct/Nov

- One Mills Lane, 30-storey office, hotel and retail, Albert St - November/December

- International Convention Centre, cnr Hobson, Wellesley and Nelson Sts - end of 2015

- Park Hyatt Hotel, Wynyard Quarter - early 2016

- Downtown centre, 36-level retail and office - May 2016

- NDG Tower, 52 levels, corner Albert, Victoria and Elliot Sts - mid-2016