Key Points:

The Government has suddenly rolled back the introduction of tolls for this Auckland Anniversary holiday weekend on the new $365 million Northern Gateway motorway extension due to open early tomorrow.

Transport Minister Steven Joyce announced late yesterday that motorists would get a free run over the sweeping 7.5km bush-clad route between Orewa and Puhoi until the end of the weekend.

Although calling the move a "great opportunity" for motorists to try out the road before having to pay to use it, he acknowledged a risk-management aspect to a decision which he said was undertaken jointly by himself and the Transport Agency.

"We are going to have a lot of people over the weekend, and it is an extra effort to make sure their first experience of the new road is a good one," he told the Weekend Herald last night.

"There will be people who don't know exactly how to use it and some will think they have to stop when they won't. There's just a risk that we could get snarl-ups so we thought it was best to set [the toll] at zero for the weekend."

Mr Joyce's surprise announcement came on the eve of an opening ceremony he will lead this morning under toll gantries at the Orewa end of the road, before the Transport agency allows motorists on it in stages through the early hours of tomorrow.

The announcement follows weeks of publicity in which the agency exhorted motorists to open pre-paid accounts on the internet or by phone so as not to have to interrupt their journeys at cash kiosks at either end of the new road.

Two cash kiosks each have been installed at a turning bay at the northern end of the road near Puhoi and at the BP Connect service centre south of Silverdale.

Those not wanting to set up an account can still drive along the road without stopping, as they will have three days to settle up by calling the freephone number 0800-402020 and pay their tolls of $2 a car or $4 a truck by quoting their credit card numbers.

But the publicity drive was hampered a fortnight ago when the agency was forced to close its website toll payment facility for a week after computer experts alerted the Herald to a basic flaw by which almost 1000 motorists sent credit card details across an insecure internet link.

Although the link was secured and restored more than a week ago, leading to 6327 pre-paid registrations, even keen supporters of the toll road have in recent days expressed reservations about perceived disincentives against setting up accounts.

These include a minimum set-up amount of $44 for a single vehicle, against which tolls will be deducted each time it passes under gantry-mounted cameras near the Orewa end of the road.

The Transport Agency says it set the sum to cater for heavy users of the road, to ensure they do not inadvertently become debtors and incur penalty charges, but has promised to investigate whether its computer software is capable of accepting a lower amount from less frequent travellers.

Mr Joyce defended the agency's decision to open what will be the country's first "free-flow" electronically-controlled toll road in the midst of a busy holiday weekend, saying it would offer much-needed congestion relief for homeward-bound motorists.

The new road includes a pair of tunnels at the northern end, and three viaducts over the Waiwera River and other bush-clad waterways.

Toll tariffs
For one-way trips (from Tuesday morning)

* Motorcycles: $0
* Cars: $2
* Trucks/buses exceeding 3.5 tonnes: $4

Penalty rates

* After 72 hours: toll plus $2.20 administration fee
* 28 days after notice sent of unpaid toll: $40

How to pay within 72 hours

* Set up an account (minimum set-up amount $40 plus $4 for each light vehicle and $8 for each truck) by visiting or phoning 0800-402020.
* Call 0800-402020 and quote credit card number (Mastercard or Visa only) for each trip taken.
* Pay by cash, Eftpos or credit card at kiosks at BP Connect service centre south of Silverdale or at turning bay beside SH1 south of Puhoi, buying up to 10 trips at a time.