"For those away on holiday who test positive you will be contacted regarding your ongoing care," the Ministry said.
Holidaymakers are being reminded to keep physically distanced while in large crowds or in poorly ventilated indoor spaces.
Those now eligible for a booster jab are being strongly encouraged to get one, as a "key defence" against the Omicron variant.
Ten new cases were detected at the border yesterday - four of which have been identified as the Omicron variant.
Among returnees to test positive were Christmas Eve arrivals from Australia and the United States who are staying in MIQ facilities in Christchurch and Auckland.
The total number of Omicron cases detected at New Zealand's border has now risen to 49.
Vaccination and testing rates plunged on December 26. Many stations were closed as Boxing Day fell on a Sunday, the Ministry said.
Just 96 people received their first dose of the Pfizer vaccine, 740 their second dose and 903 received their booster doses.
The number of tests taken on December 26 were 5716.
Forty-one people remain in hospitals battling the virus across Auckland and Tauranga, while eight are being treated in an intensive care unit.
Meanwhile Hawke's Bay District Health Board (DHB) is set to become the twelfth DHB to have 90 per cent of its eligible population fully vaccinated.
It is 192 doses short of reaching the milestone, the Ministry said.
Among 10 DHBs with active Covid-19 cases, half have 90 percent of the eligible population fully vaccinated.
New cases
Among seven new cases in the Waikato, four were detected in Te Kūiti, two in Hamilton, and one in Te Kauwhata.
Four are known contacts of previous cases, a fifth case has been linked, and the remainder are under investigation.
Two new cases were reported in Tauranga - one is a known contact of a previous case and the second is under investigation.
All three new cases reported in Rotorua are known contacts of previously reported cases.
One new case in Canterbury is a contact of an existing case. There are two active cases isolating in the region.