There were 46 new cases of Covid-19 in the community today, according to the Ministry of Health. Video / NZ Herald
Omicron cases detected at the border have risen by 17 overnight, the highest daily jump since the first case arrived in New Zealand less than a fortnight ago.
The total number of Omicron cases in the country rose from 54 to 71 on Wednesday, as genome sequencing results were confirmed.
Experts see the spike as a reflection of outbreaks happening overseas, and warn an increase in Omicron cases in MIQ will increase the likelihood of the new variant reaching the community.
Epidemiologist Michael Baker said if Omicron cases peak too high, the Government may need to take action to avoid "saturating" MIQ and the possibility of outbreaks.
Omicron cases rose by seven over Christmas Day and Boxing Day, then by four on December 27 and five on December 28.
The genome sequencing process can take a day or two, the Ministry of Health said, so the new Omicron cases detected on Wednesday did not all arrive overnight.
"The Omicron cases announced each day are not the same cases as those being announced as new cases at the border," a spokesperson said.
"The Omicron cases being announced each day are the latest results on test samples that ESR have run whole genome sequencing on. This process takes a day or more to complete after a case is identified."
University of Auckland Associate Professor Siouxsie Wiles said the spike is to be expected.
She agreed it was a reflection of the Omicron outbreaks that have plagued countries such as the United States, United Kingdom and Australia over Christmas.
Many of the infected returnees have arrived from these countries - as well as India and Qatar - between December 20 and 26.
But it's unclear which countries people infected with Omicron have arrived from.
"Cases are still rising in many, many places unfortunately. They are doubling every few days in many countries.
"We've been waiting for sequence information. We've been seeing numbers of people coming back [and] testing positive fairly higher than they have been for a while, and that reflects the fact that many more people can get Omicron compared with Delta."
People wait in line at the Otara Covid-19 testing centre in South Auckland. Photo / Alex Burton
Wiles feared the spike in Omicron cases increased the chance of the new variant entering the community.
"The big worry is how much more difficult it becomes to contain it within MIQ.
"Every case increases the risk and it's just the incredible work that needs to be done by people managing MIQ to try and keep it out."
"Not every positive case returns a whole genome sequence. Many of the results fail because the case does not have an acute infection," the ministry said in a statement.
Baker said it was important to know the status of every case detected at the border every day.
He said an increase by 17 in one day was worrying.
"It would also be at a certain point a reflect on the need for action. We do have to turn down the tap if we're getting too many infected people coming.
"Once you're in the range of 10 to 20 a day, and obviously over 20, you start to risk saturating MIQ and increase the risk of outbreaks."
The first case of Omicron was detected in New Zealand on December 16.
