Motorists on Auckland's Northern Gateway toll road - including Labour Weekend holidaymakers - will have more time to pay up despite a looming Transport Agency crackdown on laggards.

The agency has extended from three days to five days the period available to motorists to pay tolls of $2 for cars and $4 for trucks, before they become liable for an extra $2.20 to cover the cost of sending them reminder notices.

But the agency has also disclosed it is considering whether to extend its tolling net for the 7km road between Orewa and Puhoi to motorcyclists, who have been able to ride it for free since it opened in January.

It intends consulting motorcycle groups next month with the aim of completing a review by the end of this year of its free passage for the riders, who also face annual accident compensation levy rises of up to $493.

The extension of time for paying tolls comes as the agency prepares for another holiday rush on Friday on self-help kiosks at the BP Connect motorway service centre south of the gateway road, and near Puhoi on its northern approach.

It is urging motorists to avoid the hassle of queuing at the kiosks, which had to cater for daily peak crowds of up to 2900 people over Easter, and instead to pay online or by telephone within five days of using the road.

That is despite an average cost of $2.70c for collecting a toll by phone, compared with 14c online and 35c at the kiosks, according to an agency operating report for the road's first five months.

"Those who use the road on Friday will be able to pay online or by freephone the following Tuesday without incurring any additional fees," said Transport Agency regional director Wayne McDonald.

But the agency is also preparing to send infringement demands of $40 to motorists who have until now been ignoring reminder notices to pay their tolls.

The agency report disclosed $238,366 in unpaid tolls on 53,000 vehicle trips made by almost 28,000 drivers in the period to June 30, compared with $2.3 million in revenue raised from an user compliance rate of 94 per cent.

Seven of the toll dodgers owe the agency more than $300 each, and can expect to hear soon from debt recovery agents before being sent infringement notices.

But the agency has had to write off more than $31,000 in tolls owed predominantly by overseas visitors, and is considering asking the Government for a law change allowing it to recover debts from vehicle rental companies.

An agency spokesman said yesterday that existing legislation allowed owners of vehicles to avoid paying tolls if they were not the ones using the road and could provide contact details for liable drivers. He said several rental firms had elected to use the legislation to avoid trying to collect tolls from their customers.

"This process means that rental vehicles are effectively becoming exempt from paying tolls, which was not intended in the legislation, nor is there any valid reason that they should be," the spokesman said.

"Despite this issue the NZTA [Transport Agency] achieved an overall compliance level for toll payments of 94 per cent, which is a great result."

The agency is urging drivers heading north from Auckland for Labour Weekend to give themselves extra time to reach their destinations early and to take special care around roadworks sites near Puhoi, Warkworth and the turnoff from State Highway 1 to Mangawhai. Speed restrictions will remain in place.