Councils grappling with need to upgrade storm water systems after sewage contamination fears at Kiwi beaches

Summer sun seekers have been heading back to beaches after this week's storm, but a handful of spots are too polluted to swim in.

Kiwi swimmers have been advised to check the water quality at their favourite spots before taking a dip this summer. Source: 1 NEWS

As the deluge pelted the country, the storm water systems in some areas couldn't cope, which meant beaches became contaminated with sewage.

In Wellington, a resident said that even before storms they are wary of water conditions.

"We're a bit worried about the water quality because you can smell the sewage sometimes."

Water New Zealand said the water quality is a challenge that all city councils are dealing with.

"It's not just an Auckland specific problem, not just Christchurch or Wellington specific problem," Noel Roberts from Water NZ says.

When this week's downpour hit the country, some older water networks were not able to cope. Storm water mixed with waste water, which led to pollution.

Water New Zealand said some of the water networks are "starting to get a bit tired."

Auckland currently has at least 16 unsafe beaches.

Auckland Mayor Phil Goff said he wants to spent 7 billion dollars over ten years to fix the city's water problem.

"The reason that it's taken so long is that council after council has simply said it's too big a job, this is too expensive, they've left it in the too hard basket," he said.

"It's time to take it out of the too hard basket and to fix this problem now rather than passing it on to another generation unresolved."

While councils ponder the issue, the best advice for swimmers is to avoid a dip for at least two days after a storm.