Beachgoers in Auckland are being warned on Tuesday against swimming at multiple beaches after heavy rainfall caused water quality to plunge.
Safeswim said multiple popular Auckland beaches were off-limits to swimmers due to sewage overflow, while others had been slapped with red "swimming not advised" notices.
Those off limits included Narrow Neck, St Mary's Bay, Home Bay, Herne Bay, Judges Bay, Okahu Bay, Te Tinana, Ōrākei Basin, Pt England and Howick.
Beaches where swimming wasn't advised included Big Manly, Browns Bay, Christmas Beach, Castor Bay, Wairau Outlet, Milford, Takapuna, Little Shoal Bay, Bayswater, Cheltenham, Masefield Beach, Karanga Plaza, Mission Bay, St Heliers, Mellons Bay, Kawakawa Bay and Sandspit.
"Safeswim water quality models predict that levels of faecal indicator bacteria breach national guidelines for swimming, based on guidance published by the Ministry of Health and Ministry for the Environment," the red warnings say.
Auckland has been working to fix its aging wastewater pipes.
Heavy rain causes the Super City's sewage system to overflow and be discharged into the ocean, polluting it with faecal bacteria.
As a result, Auckland Council-owned Watercare has invested $11 billion to try and reduce the problem. Still, it's been revealed it could take two decades to solve 80 percent of the issue.
"Aucklanders have a right to expect they take appropriate steps to minimise and prevent these sorts of overflow events occurring," Finance Minister Nicola Willis said last month, noting sewerage management was the responsibility of local Government.
Meanwhile, temperatures in New Zealand's largest city were expected to climb back towards the 30s over the next few days.
MetService was predicting a maximum temperature of 28C in Auckland on Wednesday, Friday, Saturday and Sunday.
In the South Island, it's expected to be even hotter - with the temperature in Christchurch expected to top 30C on Friday and Saturday, the forecaster said.
Officials said fire bans remained for parts of the country including Marlborough, mid-south Canterbury, central Otago and the Far North given the hot and dry conditions in those areas.
Newshub.
