Agency regional director Stephen Town said in response to the AA that the centre did not previously experience any significant increase in calls at weekends, even those extended by public holidays, and that motorists had five days to pay their tolls.
"The feedback we have received to date ... indicates that drivers have not been inconvenienced," he said.
At the same time as changing the centre hours, the agency introduced administration fees on top of its tolls, which remain $2 for cars and motorbikes and $4 for trucks and buses, for motorists choosing to pay at off-road kiosks or by phone.
Those paying at kiosks are charged 40c extra, and call centre transactions cost $3.70c more, although there is no administration fee for motorists with pre-paid accounts or who settle online.
The agency on Tuesday suggested drivers pay before leaving home over Labour weekend, which it said would be particularly busy because of the Rugby World Cup final.
But it disclosed it was also trying to cobble together a second payment kiosk at the Puhoi end of the toll road, from the remnants of two machines destroyed by suspected thieves.
ON THE WEB
PAYING FEES
* No phone payments will be possible over Labour weekend for the Northern Gateway toll road.
* Fees are $2 for cars and motorbikes and $4 for trucks and buses, if you pay at off-road kiosks or by phone.
* Payments at the kiosks cost 40c extra, and call centre transactions cost $3.70c more.
* People are encouraged to pay online before they leave home.