Sewage and wastewater overflows pour into waters around Auckland after heavy storms, causing public health warnings and swimming bans. (File photo)

Auckland swimmers will get real-time information on water quality at the city's beaches, starting this summer.

On Thursday, Mayor Phil Goff announced that an upgrade to the council's water quality monitoring system, Safeswim, will go live from November 1.

The upgraded programme will be a New Zealand first, giving Aucklanders real-time information on where and when it is safe to swim.

MATTHEW CATTIN/STUFF Auckland mayor Phil Goff announced plans to upgrade Auckland's water monitoring system Safeswim in time for summer on Thursday. (file photo)

It was important to be transparent and honest with the public as water quality at Auckland beaches was "worse than we would like to believe," Goff said.

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"People have a right to know, and [council] have an obligation not just to warn them about poor quality but get on and tackle the causes of it."

For example, there were 70 sites along the western isthmus area - from the CBD to Pt Chevalier and Te Atatu - where waste water was disgorged into streams and the coast between 25 and 60 times a year at each site, Goff said.

"That is a huge problem. It's a not a new problem, but time we dealt with it."

While the current water monitoring system was compliant with New Zealand national standards set in 2003, these were not "fit for purpose", Goff said.

Currently the public could access information about the quality of water at a beach but by the time they were reading it the information was already out of date, he said.

"The new system is set to be 20 times more accurate than we have been operating."

Safeswim covers 83 beaches in the greater Auckland region, with 69 monitored regularly.

A real-time alert function would inform the public of "unpredictable risk events" as soon as they were detected, such as sewage overflows or shark sightings.

Safeswim would also measure wave and wind conditions, tides, rips and the presence of jellyfish.

Nine Auckland beaches are not monitored because they consistently have very good water quality, while another five are not monitored due to permanent "no swimming" warnings - Cox's Bay, Meola Reef, Weymouth, the Wairau Stream outlet at Milford Beach and Little Oneroa lagoon on Waiheke Island.

The root problem - wastewater and stormwater overflow - was not new but Aucklanders needed to take responsibility for it now, Goff said.

Earlier this year, the low pressure weather system dubbed the Tasman Tempest showed just how fragile some of Auckland's stormwater systems could be, spilling waste into the harbours and forcing swimming bans.

In February the Ministry for Primary Industries warned against eating shellfish from the Mahurangi Harbour in the Hauraki Gulf after oysters were found to have been contaminated with norovirus, likely caused by leaking septic tanks.

While it was "unacceptable" that some beaches were off limits, the upgraded Safeswim programme and work Council and Watercare were doing to prevent wastewater and stormwater overflows would go a long way to improving water quality, Goff said.

Auckland Council planned to build its massive "central interceptor" project in 2019 which will include a $960 million, 13km underground tunnel that will deliver up to two million cubic metres of sewage and stormwater to a proposed Mangere treatment plant every year.

The Safeswim upgrade is part of a larger plan by the council and Watercare to significantly expand the work needed to clean up Auckland's beaches, Goff said.

"If you're talking about '100 per cent pure New Zealand' at some stage you have to either change the branding, or start walking the talk".