Auckland commuters are already caught up in a long, slow crawl to work this morning, with central city roads closed as firefighters battle the SkyCity inferno.
Auckland Civil Defence is urging people to avoid the city altogether.
Much of Nelson St is closed - creating havoc for traffic entering the city from the busy northwestern motorway. Traffic maps show dozens of pinchpoints around the city at 8am.
More than 20 fire engines were lined up along Nelson St with ground-based firefighters using high-powered hoses to try to quell flames.
Auckland Transport warned commuters to expect major delays in the central city.
Spokesman Mark Hannan said the immediate roads around SkyCity - including Hobson, Victoria, Nelson and Wellesley Sts - would remain closed until at least mid-morning.
"It will be a slow journey in [on Wednesday]. If you can avoid coming into the city, do."
People who could work from home or from a non-central location this morning, or start work later in the day, were recommended to do so.
Meanwhile, Auckland Emergency Management acting director Sarah Sinclair advised commuters to take extra care, be patient and stay out of smoke plumes.
"There will be ongoing disruption [Wednesday] morning, while roads remain closed and public transport is diverted.
"We urge people to use their common sense and not put themselves in harm's way by standing in smoke plumes or downwind of smoke."
• Workers flee giant blaze, black smoke chokes Auckland
• Firefighters battle blaze into Wednesday morning
• Aucklanders advised to avoid central city amid fire disruptions
• Witnesses describe huge blaze at International Convention Centre
Disruption to City bus services
NX2 to city
Buses will use Port motorway off-ramp, left Wellesley Street, left Mayoral Drive, left Wakefield Street, left Symonds Street, left Wellesley Street, with buses ending their trip on Wellesley Street near AUT (7089).
22A, 22N, 22R, 221X, 223X, 24B, 24R, 24W, 243X, and 248X to city
Wellesley Street as normal then left Mayoral Drive via Cook Street, right Nelson Street, left Wellesley Street, then as normal.
82, 802, 923, and 924 to city
Fanshawe Street as normal via Sturdee Street, via Customs Street, right Queen Street, left Wakefield Street then as normal.
75 to city
Wellesley Street as normal, left Mayoral Drive, via Cook Street, right Nelson Street, left Wellesley Street, then as normal.
18, 151X, 171X, 172X, 195X, and 209 to city
Queen Street as normal, left Wellesley Street, end trip outside The Civic.
Customs Street as normal, via Fanshawe Street, left Halsey Street, right Victoria Street, then as normal.
105 and 106
Buses will depart ANZ Bank bus stop as normal, left Halsey Street, right Victoria Street, left Franklin Road, then as normal.
110, 125X, 129, 132, 132X, 133, 133X, and 134
Nelson Street as normal, right Cook Street via Mayoral Drive, left Queen Street, left Mayoral Drive, end trip at Mayoral Drive near Greys Avenue.
Wellesley Street East as normal, right Queen Street, left Customs Street via Fanshawe Street, left Halsey Street, right Victoria Street then as normal.