Bus and ferry services will be bolstered in Auckland from tomorrow to encourage people to leave their cars at home while the harbour bridge is at half capacity.
On Friday, strong wind gusts forced a truck to shear off a key part of the bridge, and lane closures have been causing traffic problems since then.
Heavy congestion is expected at peak hours on north and west Auckland motorways with the eight-lane bridge reduced to four while it's repaired.
Auckland Transport chief executive Shane Ellison said there will be 14,000 extra seats on buses and ferries from tomorrow.
He said commute times will be a lot slower, but with the Northern Busway, public transport will be the fastest option.
"Yes there will be a difference - there will be congestion. For those in private motor vehicles probably more than ever. The busway dedicated infrastructure is a great time for people to use buses. The time differential will be significant."
The Transport Agency hopes to have a clearer idea by the end of the day about when some lanes can be reopened on the damaged Auckland Harbour Bridge.
The senior journey manager, Neil Walker, said nine engineers have been examining a strut that was hit by the truck.
"It seems to be only related to the main spar that got struck or the strut that was hit. Their job today is to really try and firm that up for us - what do they think they can do to actually get some lanes open?"
Walker said the damaged bridge is causing significant knock-on effects for traffic across the Auckland transport network, as motorists switch to the Western Ring Route.
The Transport Agency's general manager of transport services Brett Gliddon said repairs won't be easy.
"If we're going to do a temporary fix it's going to be a week or so but there are no guarantees it's going to work."
He said freight vehicles can safely cross the bridge, although drivers are being encouraged to use the Western Ring Route to avoid congestion.