A microbiologist who completed a stint in managed isolation believes there's a number of weak spots in MIQ.
It has been confirmed a Northland woman caught the more infectious South African Strain of Covid-19 from another returnee while they were both in managed isolation at Auckland's Pullman Hotel.
But health officials do not know exactly how it was transmitted between the pair.
Dr Duncan McMillan - who spent 14 days in isolation in the Novotel at Auckland Airport in November - told Checkpoint about his MIQ experience in November.
Dr McMillan said he thought it would only be a matter of time before someone was going to be transmit the virus within MIQ.
"One of the things that makes me say that is immediately after exiting the plane I noticed that social distancing really wasn't happening, it was getting more and more crowded as you got to the bus."
He also claims his room didn't seem to be clean, and that cleaning should be done at a hospital level grade to stop transmission of the virus.
"I had some facial hair around the bathroom and there was a used milk carton in the fridge and that's when I started to have a look a lot more closely at what was going on. It really wasn't my intention to go there and do an audit, but I felt compelled after seeing these fairly obvious problems."
He said he was pushed to write a letter to the Minister in charge of Covid-19 Response after an incident in which he saw newly arrived guests in the same general exercise or rest area as those who were nearly done with their isolation period.
"That for me presents a big problem because throughout the stay there I didn't see frequent washing of the lift buttons and that's the immediate contact point between people."
Although that was before the day one or zero testing was introduced. With this requirement, those undertaking that test are not allowed to leave their room before returning a negative result.
Dr McMillan said in his view, people should stay in their rooms for the first three to five days.
"I've been through MIQ, I know it's not an easy thing to do for anybody ... but I do wonder if this is the best way to prevent spread."
However, he said MIQ changes that have taken place since November may have made a difference to what he had experienced.
In an interview with Checkpoint, Director-General of Health Ashley Bloomfield said the system could never be 100 percent but he has full confidence in the system.