Drivers will be able to check the traffic online before leaving home, and in transit

Traffic conditions around the notorious Kopu Bridge near Thames will be filmed on a closed-circuit TV camera over Christmas, to warn motorists if queues build up.

The Transport Agency, which is building a $47 million replacement bridge up the Waihou River from the existing one-lane structure, is installing the camera this week with a direct all-hours connection to its Auckland traffic operations centre.

That will enable it to send regular traffic updates 24 hours a day until the end of January to radio stations and its website - - for motorists to consult online before leaving home or on mobile consoles during road-side breaks in their journeys.

Looking up the website while driving would be illegal, in the same way as talking on mobile phones at the wheel is banned, and punishable with an $80 fine and 20 demerit points.

The agency hopes to ease congestion by encouraging motorists to delay their journeys or choose an alternative route.

Traffic surveillance cameras have until now been used only in Auckland and other main centres. The agency has used roadside electronic message signs to encourage motorists to avoid the bridge route at busy times, when it can take more than an hour to cross the Waihou River.

But Waikato-Bay of Plenty regional director Harry Wilson said the amount of holiday-season congestion around the 465m Kopu Bridge, on which the single lane is controlled by traffic lights, justified expanding the surveillance network.

"Over the holiday period, traffic on the Kopu Bridge and the roads leading to the bridge can be incredibly heavy," he said.

"It makes for a frustrating start to the holidays and can cause major inconvenience to locals, so anything we can do to minimise that is a good thing."

Mr Wilson acknowledged traffic conditions could change rapidly after motorists consulted the website, and they should also listen for radio updates on the journey.

Motorists who miss the cue to avoid the bridge this summer will at least have something new to look at as they inch towards the traffic lights for their turn to cross the Waihou.

Construction has begun from the river's western bank of a platform to build piers for the new 580m two-lane steel bridge to be completed by mid-2012, 28m upstream from the existing structure.

The platform will be built out to the existing bridge's swing span, which opens to let large boats pass, and it will support a piling rig for the new piers.

The replacement bridge project, which was brought forward under a $500 million jobs and growth plan announced by the Government early this year, will include 2.5km of new approach roads and a four-leg roundabout to replace the difficult intersection of State Highways 25 and 26.