Already reached - expert

of having undetected cases in New Zealand, he said.

‘‘Once you get to 28 days since the last infectious person was put into isolation, then you have a 95 per cent chance of elimination.’’

According to modelling by the University of Otago, which lined up with Te Pu¯ naha Matatin research centre in Auckland, there was now a very likely (well above a 95 per cent chance) New Zealand had completely eliminated the virus, Baker said.

Cabinet would have used this modelling when making decision last week, he said.

There was a need for the Ministry of Health to improve the data it presented on its website, so the country could backtrack its progress to elimination – a date Baker said the country reached ‘‘with a reasonable degree of certainty’’ on Monday, June 8.

The country needed a point for reference and something the ministry could be ‘‘celebrating,’’ he said.

This was a problem he had

its raised repeatedly with the ministry.

‘‘I have found it frustrating that this date has not been put up for all New Zealanders to see.

‘‘This is a critical date for New Zealanders, so I think it is something that should feature on the ministry website to say, ‘this is the last date that a person got infected in New Zealand /locally acquired case was put into isolation’, therefore the clock started ticking from there.’’

This would exclude people who came from overseas and were found to have the virus but were in quarantine.

The fact Cabinet and its advisers concluded the country could move to level 1 immediately was a very strong statement that in their view the virus was eliminated, he said. ‘‘It all added up last Monday. I think that is the date we should use.’’

Politicians got a bit nervous about having a definition of elimination and may feel that it might set them up to fail, he said.

‘‘By the time Cabinet met on Monday, it was a pretty reasonable time to say elimination has been achieved.’’ Professor Michael Baker

confirmed and probable Covid-19 cases in New Zealand