There are 35 new cases of Covid-19 in the community today and 24 cases that were detected at MIQ facilities, the Ministry of Health has announced. 

The data comes as one expert warns that the highly infectious Omicron variant could leak from MIQ facilities in a matter of weeks - potentially causing an outbreak by the end of this month. 

Of the new community cases, 18 are in Auckland, 13 in Bay of Plenty, three in the Lakes district and one in Waikato. 

There are 37 cases in hospital, one less than yesterday. 

The vast majority of hospitalised cases are in Auckland, with four at North Shore Hospital, 14 at Auckland Hospital and 13 and Middlemore. Additionally, there are five hospitalisations in Tauranga and one in Waikato. 

Three of the cases are in intensive care or high-dependency units - two at Middlemore and one in Tauranga. 

The number of booster doses continues to increase, with the requirement for booster shots changed this week from six months to four months. 

There were 43,219 booster doses administered in the past 24 hours, roughly 2000 more than yesterday's total. 

Yesterday, the Ministry of Health revealed just 19 Covid-19 cases in the community - none of them the Omicron variant - but more than twice as many cases in MIQ. While it's not yet known how many of the MIQ cases are the Omicron variant, the ministry has acknowledged that Omicron is now likely to be the most prevalent at the border. 

University of Canterbury professor Michael Plank said it was imperative that New Zealand prepared for the possibility of a summer outbreak, urging everyone eligible for a booster vaccine to get one right away. 

He said parents should be prepared to get children between the ages of 5 and 11 vaccinated as soon as they are eligible on January 17. 

For many, yesterday's statistics would have initially seemed uplifting, with the community cases seeming to stay low as vaccination rates continue to rise and warm weather pushes people outdoors, where it's harder for the virus to get a foothold. But the rapidly increasing MIQ numbers tell a different story, experts say. 

For most of last year, MIQ was seeing about two or three cases a day, compared to 43 new cases yesterday. If that trend continues, Plank said, Omicron could be circulating in the community "in 18 days rather than 180 days". 

While it's impossible to know for certain whether it will be weeks or months, the recent MIQ numbers make it clear that "there's a very high risk at the moment", he said. 

It's a sentiment shared by University of Melbourne epidemiologist Tony Blakely, who told RNZ yesterday that New Zealand should do its best to keep its borders as strong as possible and in the meantime "boost like crazy". Omicron will get into the community at some point, he warned. 

Yesterday saw a huge increase in people receiving booster jabs, thanks to a new rule kicking in that calls for boosters after four months instead of six. Over 41,000 people queued up for boosters. 

Children's vaccines, meanwhile, are expected to arrive in New Zealand tomorrow. Deliveries to vaccination sites will begin Monday, after the doses are thawed, repackaged and checked for quality assurance, a Ministry of Health spokesperson said. 

There should be plenty of supply, so the speed of the rollout will depend on the willingness of parents to get their children vaccinated, said Covid-19 Response Minister Chris Hipkins. 

The children's vaccine will be available at all vaccination centres starting January 17, and appointments can be made at bookmyvaccine.nz. It will be up to individual school boards to decide if vaccines are distributed on campuses, officials have said. 

Of the 19 new community cases announced yesterday, six were in Auckland and Waikato and Bay of Plenty each had five cases. Additionally, Taranaki had two new cases and Northland reported one. 

As of yesterday, there were 38 people hospitalised with Covid-19 - four in Tauranga and the rest at hospitals in Auckland.