High tides expected

Drivers are being warned about the risk of flooding on the city's motorway network.

Exceptionally high tides are forecast for the Manukau and Waitemata harbours this week.

The NZ Transport Agency  is advising commuters that some low lying sections of the network may flood.

In the Waitemata  harbour, high tides of up to 3.7m - about 0.6m higher than normal - are expected for five days from tomorrow.

Areas most at risk from flooding include a section of highway and adjoining cycleway on the Northwestern Motorway causeway between Great North and Rosebank Roads, and the Northern Motorway (SH1) near the Onewa Road interchange. 

The king tides will be at their highest on Saturday and Sunday mornings.

Transport Agency National Journey Manager Kathryn Musgrave says. ''Our advice to all road users, including cyclists and walkers, is to take extra care - especially during that hour-and-a-half either side of high tide,'' she says.

''If necessary, we will divert drivers to other roads to allow them to continue their journeys safely. Sections of the Northwestern cycleway will most likely be underwater which will make walking and cycling hazardous.''

The Transport Agency's SH16 Causeway Upgrade Project includes raising this section of the Northwestern Motorway 1.5m to prevent future flooding.

The king tides occur when the moon is new or full and closest to the earth.

The weather - low pressures or strong winds - can also influence the height of the tide. 

(Live Matches)