Auckland motorists should prepare for lane closures around the city this weekend.
The two southbound lanes of the Auckland Harbour Bridge as well as the Shelly Beach Rd off-ramp, will be closed from just after midnight on Saturday until 10am on Sunday for the annual Bike the Bridge event.
Three traffic lanes over the Auckland Harbour Bridge in each direction would remain open throughout that period, the New Zealand Transport Agency's acting highway manager Tim Crow said.
Access to State Highway 1 city bound will also be closed at the Onewa Road Interchange.
The temporary changes meant drivers would be separated from hundreds of cyclists by a line of buses parked in the left-hand lane from Esmonde interchange to the bridge, so everyone needed to be alert and take extra care, Mr Crow said.
"The event is timed early in the morning when traffic volumes are light, to reduce the disruption to drivers as much as possible, but delays are still likely and people should allow more time for their journey on Sunday," he said.
The Northern Busway between Constellation Station and Onewa Interchange would also be closed and there would be some disruption to local bus services.
Significant lane restrictions would also have an impact on drivers using the Te Atatu interchange on State Highway 16 from 10pm today until 5am on Monday.
To safely accommodate additional traffic volumes on the newly widened and raised Te Atatu Bridge, extra strengthening on the western side of the bridge was needed.
"Although traffic levels are quieter over a weekend, delays are still likely," said Mr Crow.
"To help us complete the work as quickly as possible we are asking people to stay off the affected roads, use alternative routes, or allow plenty of time to get through the interchange."
This work was part of the Te Atatu Interchange Upgrade Project, which is widening the five existing motorway on-ramps and exits at Te Atatu and improving access for vehicles, cyclists and pedestrians. It will also widen the Northwestern motorway between the Te Atatu interchange and Henderson Creek. The project is due to be completed early 2016.