NZTA warns of motorway flood risk

The NZTA is warning of possible flooding on Auckland's Northwestern Motorway over the next few days due to unusually high tides in the Waitemata Harbour.

High tides of up to 3.5m - about 40cm higher than normal - will occur from Saturday until Wednesday.

The section most likely to be affected lies between the Patiki Road Interchange and the Rosebank Road bridges.

The cycleway there will be flooded, and cyclists are advised to avoid using it 90 minutes either side of the high tide mark.

"It is unlikely the motorway itself will be affected, unless weather conditions like strong winds have an impact on the tides, but people should still drive with care when using this section of highway," said State Highways Manager Tommy Parker.

"There is a traffic management plan to re-direct traffic away from the causeway if there is flooding."

The NZTA is planning to raise the causeway by 1.5 metres and widen the motorway to provide extra lanes as part of the Western Ring Route development.

For more information on tide times, alternative routes or planned detours and closures call NZTA on 09 5200 200.