Lead should be phased out of plumbing for drinking water in New Zealand, an environmental expert says.

The call comes on the heel of a Ministry of Health report into lead contamination found in East Otago drinking water supplies.

The report, released at the end of March, says better regulation is needed for drinking water, and also recommends a review of plumbing standards for lead in taps and pipe fittings.

The East Otago contamination, where lead levels tested as high as almost 40 times the acceptable limit for drinking water, is still being investigated, but household taps and pipe fittings containing lead are widely used throughout this country.

University of Canterbury director of environmental science Sally Gaw said there should be no lead in taps for drinking water, and it was important the review into plumbing standards is done.

"Lead is a neurotoxin, it's not great at all for young children or babies to be drinking water that contains lead. [Only] a very low level of exposure to lead is considered to be safe - if at all," professor Gaw said.

The heavy metal is often added to brass alloys. The Master Plumbers organisation, in 2018 called on the government to ban the sale of plumbing products containing dangerous levels of lead.

The organisation had five New Zealand- supplied taps tested in a laboratory, and found one leached lead at levels 70 percent higher than either the New Zealand or Australian standards.

Master Plumbers chief executive Greg Wallace said at the time the problem was a hidden danger, and householders here should be concerned about research done in Australia that found 8 percent of a sample of suburban houses had plumbing that was leaching lead into water at unsafe levels.

"The drinking standard for New Zealand is far too high, we're double the allowable level compared to Europe, Sweden and even China. So that needs to be reduced for a start, Wallace told Morning Report.

"The problem for New Zealanders, is there's no way to identify this product - in Australia they have a system called Watermark... we're calling for third party verification, we think the standards in New Zealand are not being policed, and the only way to police those standards is to have some sort of third party verification for products being sold."

Professor Gaw said New Zealand's ageing water supply infrastructure creates vulnerabilities.

She also backed a call for laboratories that test drinking water to report all excessive contamination to the director-general of health - another recommendation in the report into the East Otago lead contamination.

The further level of scrutiny could help pick up problems when test results were sent to different agencies, she said: "I think that

is a great step forward, and will help stop things getting lost."

A World Health Organisation fact sheet on lead said the metal had caused significant public health problems in many parts of the world, and "there is no level of exposure to lead that is known to be without harmful effects."

Young children are especially vulnerable to exposure, which can cause "profound and permanent" health problems.

Lead exposure has been linked to irreversible brain development problems, behavioural disorders, difficulty learning, anger and violence, and kidney problems.

The US banned lead in new tapware in 1986, and Australian authorities are also considering drinking water exposure from plumbing fittings

A new national agency, Taumata Arowai, will regulate drinking water from July.

Taumata Arowai was founded in the wake of the Havelock North water contamination connected to the death of four people, and the poisoning of at least 5000 people, after which led to a government inquiry that found systemic failings in the regulatory framework for drinking water.