The Southern District Health Board (SDHB) says it did not advise the local council not to go public when lead contamination was found in East Otago drinking water.
Earlier this month, residents in Waikouaiti, Karitane and Hawksbury Village were told not to drink or cook with their tap water after lead was detected in the reservoir.
Within days of the no-drink notice, Dunedin City Mayor Aaron Hawkins told Checkpoint that council staff did not advise the public of the elevated lead level back in August following advice from Public Health South.
However, Southern DHB's Medical Officer of Health Dr Susan Jack said that was not the case.
"For a one off exceedance, the recommendation and guidelines are to increase the testing to work out if there's a possible reason why it was elevated and then if there are obviously more results, then action would be taken," she said.
"Our recommendation was to increase the testing, we didn't advise that they shouldn't go public. But the usual process is that you would not go public with that information if they're following the recommendations of increasing the testing and working out what's going on."
As for any plans to change that process, Dr Jack said the Water Services Bill that would support the new drinking water regulator was out for consultation and that would likely be an area closely looked at.
More than 1000 people have had their blood tested for lead contamination since the no-drink notice was issued with a community testing clinic in place in Waikouaiti from Tuesday until Friday.
Results have already started returning with residents describing a mix of relief and confusion.
The World Health Organization states on its website there is no level of exposure to lead that is known to be without harmful effects and lower exposure levels could still cause health problems.
Dr Jack said the SDHB was using an internationally accepted threshold for lead blood levels that the New Zealand guidelines were going to be using just as a cutoff for its management.
"We're not planning to reconsider that threshold. Anyone above that 0.24 gets a call from our public health unit and a detailed discussion about what their possible exposures may be," she said.
"We are taking a conservative approach and we're using the internationally accepted reference value of 0.24 micromoles per litre for all ages. This is the equivalent to five micrograms per decilitre (a tenth of a litre) that people may have seen in WHO and other guidelines."
She recommended people consider what their potential exposure points were and to try and reduce them.
"We will be working with people to look at their possible lead exposures so whether that be in your house or from work or for hobbies, so for example, if people have an old house and they're stripping back paint, making sure that our especially vulnerable populations are not being exposed to that and that's being done in a safe manner."
Dr Jack said the SDHB would be guided by the Ministry of Health if anyone has been affected by lead.
"Our bodies do not need it for any biological use so if we do have lead in our bodies, it's not normal."
On Friday, Director-General of Health Ashley Bloomfield confirmed Dr Heather Uwins-England and Dr Jill McKenzie would undertake the review into the health system response.