The Transport Agency says it cannot promise Auckland's new Waterview Tunnel will actually speed-up your rush hour commute.

After years of waiting, motorists can now finally drive through the 2.4 kilometre tunnel, which links the South-Western Motorway up with the North-Western.

Newstalk ZB revealed earlier this year motorists will have to wait at ramp signals at the new Waterview interchange.

During busy periods, motorists will have wait in queues to enter or exit the northern end of the South-Western Motorway, unless they are heading north-west.

Signals will also operate on the southern end of the tunnel, on the on-ramps at Maioro Street.

New Zealand Transport Agency Auckland highways manager Brett Gliddon said the tunnel will complete a missing link and reduce pressure on local roads, but it won't prevent traffic jams.

"We've always said it's never going to fix peak-time congestion. There will some peak congestion in Auckland in the morning and afternoon. This tunnel was never about fixing that, so people can still expect that."

The tunnel will create the first direct motorway connection between Auckland Airport and the CBD and is expected to reduce pressure on local roads.

Large numbers of curious motorists are expected to drive through the highly anticipated tunnel during its opening weeks.

Gliddon said it could time a while for people to start to notice fewer people using local roads to get to the airport or to get across town.

"You've got to remember an additional six lanes and we've completed a link that was missing. People will notice a difference. It will take a wee while to settle down, but it will definitely make a difference."

Auckland mayor Phil Goff and transport commentators have criticised the lack of public transport alternatives to driving through the tunnel.

The Government does not plan to fund a light rail alternative, connecting Auckland Airport and the CBD through a route like Dominion Road, for three decades.

The tunnel also does not have busways and there are no equivalent busways incorporating the same route.