On Monday afternoon, the National party leader announced he had caught the virus.
"I have not been showing Covid-19 symptoms, but have been testing myself regularly as a precaution," he said.
"The test earlier today returned a positive result and I am now isolating at home with my family, who have all tested negative."
Mr Luxon says he feels fine and will join in parliament remotely this week.
New Zealand's COVID-19 rules mandate that he must isolate for 10 days.
Mr Luxon is among 192,000 - or roughly four per cent of New Zealand's population - seen as an active case.
Hospital admissions in New Zealand have risen for the 25th straight day as the Omicron variant continues to spread across the country.
On Monday, health officials reported 696 people in New Zealand's hospitals had COVID-19, including 13 in intensive care.
Both of those figures are records, overtaking the depths of New Zealand's Delta outbreak last year.
The Ministry of Health also announced 17,522 new community COVID-19 cases, however there is significant doubt over reporting of case data.
As of last week, and in response to growing case numbers, Kiwis who take rapid antigen tests (RAT) must report their result.
Public health experts believe many aren't telling the government their RAT result, either because they don't know they have to, or because they don't want to.
Case counts have dropped since Thursday last week when a record 23,183 community cases were announced.
University of Auckland epidemiologist Rod Jackson said the reporting issue meant it was impossible to tell whether a peak had been hit.
"You can't make anything of these numbers ... we could have two to three times the (daily case) numbers," he told Radio NZ.
"It may be coming down. It's unlikely. It could be going up. We just don't know. The numbers don't help any more."
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