Families in Otago towns Karitane and Waikouaiti worried for health of young children after toxic levels of lead found in water

Families of young children in Otago are shocked and worried they've been living with toxic levels of lead in their water for months.

They now have serious health concerns after the levels were found to be four-times what is acceptable.

It affects around 1500 people in Waikouaiti and Karitane, about half an hour north of Dunedin, who have been told by the Dunedin City Council to not use tap water for drinking, cooking, or preparing food until further notice as a precaution.

Waikouaiti local Ashley Thompson is worried about the health of her eight-month-old son.

"He's bottle-fed, so I've been boiling all his bottles. So I'm just a bit worried for him really," she says.

So too is Richard Olsen, whose baby is just a week old.

"Yeah, [my] wife had been drinking quite a lot of water and then breastfeeding as well. So yeah pretty bloody concerned about it," he says.

His wife is one of many booking blood tests to check lead levels in their bodies.

A large water tanker has since parked up on the Karitane beachfront to supply water to locals.

There's outrage over how long it took the Dunedin City Council to raise the alarm around high levels of lead in the water supply

Testing was carried out in early December that revealed lead levels were almost four-times the acceptable level.

The results were emailed to a council staffer 10 days later, but they had gone on leave.

"It's shocking. This is eight weeks, the first test was eight weeks ago," Karitane School Board of Trustees chairperson Jane Schofield says.

Extra water has been brought in at Karitane School to allow the first day of classes to continue.

The town supply can still be used for washing, but not for drinking or cooking food.

"The concern is that the people who are boiling water with the lead in it, it's actually causing it to be concentrated. So instead of improving the situation, they're making it worse," Schofield says.

The Council is still searching to find the cause of lead in the water supply and there is no timeframe for how long the disruption will continue.