Delta cases isolating at the Grand Mercure in Wellington are allowed to leave their rooms and use the hotel's "fresh air" area, which is an underground car park.
The joint head of managed isolation and quarantine, brigadier Rose King, says quarantine is a challenging time, and being able to access fresh air supports wellbeing.
But aerosol chemist at the University of Auckland, Dr Joel Rindelaub, says moving Covid-19 cases through the hotel is a risk.
