New Zealand Prime Minister Jacinda Ardern said on Monday that there were early signs that new COVID-19 cases were falling, even as hospitalisations jumped to their highest level since March.

New Zealand recorded 6,910 new COVID cases on Monday, well below average levels over the past week, according to data from the health ministry.

However, the number of people in hospital with COVID jumped to 836, the most since March 29 when 842 COVID patients were in hospital.

Ardern told a weekly news conference that authorities had seen a drop in the prevalence of COVID in wastewater, which suggested there might be a further decline in cases.

"Even when case number come away, it takes us about two weeks to see that really shift our hospitalisations," she said, adding that it was therefore important to watch hospitalisation numbers in coming days.

New Zealand closed its border in early 2020 as the coronavirus was spreading around the world and imposed lockdowns and strict social distancing to keep its infection low.

The COVID death toll in the country of 5.1 million people is 2,006.

It began re-opening its border in February and will lift the last restrictions at the end of this month.

The Omicron BA.5 sub-variant is driving New Zealand's infections with 59,445 active cases in the past seven days, although authorities say many infections are unreported.

Ardern said there was also some suggestion that cases might have been under reported during the recent school holidays. (Reporting by Lucy Craymer; Editing by Robert Birsel)