Motorists travelling over the single-lane Kopu Bridge this Saturday are being advised to expect delays.

NZ Transport Agency project services manager Bryce Carter says this weekend's predicted delays are likely to be the last at this traffic bottleneck.

An early design drawing of the new Kopu Bridge – State Highway 25.

An official opening of the new two-lane bridge is on Saturday morning and the public is invited to walk the bridge before it is opened to traffic next week.

While the bridge and approach roads will open next week, other parts of the project will not be completed until early in the new year.

The bridge walkover starts at 10.30am and ends at 4.30pm.

Bryce says Saturday events are going to generate extra traffic and some delays are inevitable.

'We have done everything we can to minimise traffic delays.

'Special parking has been provided on both sides of the bridge, with free buses transporting people on and off the site.

'We will have personnel on hand to manually control the traffic signals on the old bridge when necessary to clear traffic queues, however, there are still likely to be delays at times.”

He says the bridge walk was originally planned to start at 9am, but this was changed to 10.30am to allow the official opening ceremony to begin at 10am.

On the Coromandel side of the bridge, free parking is available at Rhodes Park – the sports ground south of Thames – with free buses running about every 15 minutes to and from the bridge.

Shuttles for people with disabilities will also run to and from Rhodes Park.

On the Hauraki Plains side, free farm parking will be signposted, with visitors able to walk or take a shuttle to the bridge.

There is no parking on the project site and limited parking in the Kopu industrial area.