The government is being urged to stop using any managed isolation hotels that allow air to be distributed between different rooms.
A Northland woman who tested positive for Covid-19 days after she left managed isolation, has sparking a contact tracing and testing response across Northland and Auckland.
Health officials are confident she caught the virus from another guest and are investigating how - including whether it was through the ventilation system.
A leading doctor says the hotels were not designed for disease control and any that could aid the spread of Covid-19 should be taken offline immediately.
Here's RNZ Health Correspondent Rowan Quinn.