Director-General of Health Dr Ashley Bloomfield says airborne particles from bowel movements are "not a route of infection" in the recent Covid-19 outbreak at the Pullman Hotel managed isolation facility.
A number of guests who did their managed isolation at the central Auckland hotel later tested positive for Covid-19, despite being allowed to leave after passing their mandatory tests.
Officials have been testing a number of theories about how they became infected.
A Ministry of Health report into the Pullman Hotel outbreak last month has made several recommendations but admits the cause of spread amongst guests may never be known.
Ventilation has long been one of the suspected spreaders of the virus between hotel guests.
The report said because airborne viruses can be generated by bowel movements, it wants to check the hotel's bathroom exhaust fans meet Building Code fresh air standards.
Ventilation in the lifts also remains a concern, the report said.
"I haven't seen any evidence around this," Dr Bloomfield said in response to a question at today's Ministry of Health news conference about the faecal matter theory.
"This is a respiratory infection. It's not uncommon for these sorts of viruses to be shared in faecal matter, but it's not, in this case and in other cases, a route of infection.
"I haven't seen any evidence around that."