New Zealand prime minister Jacinda Ardern tests positive for Covid-19

Due to the positive RAT, Ardern will be required to isolate until the morning of May 21, and undertake what duties she can remotely this week.

New Zealand Prime Minister Jacinda Ardern tested positive for COVID-19 with moderate symptoms, her office said in a statement on Saturday.

New Zealand prime minister Jacinda Ardern tests positive for Covid-19 (Reuters file photo)

She will not be in Parliament for the government's Emissions Reduction Plan on Monday and the coming Budget on Thursday.

"Travel arrangements for her trade mission to the United States are unaffected at this stage," the statement added.

Ardern had been symptomatic since Friday evening, returning a weak positive at night and a clear positive on Saturday morning on a Rapid Antigen Test (RAT), the statement said.

At this stage her symptoms are moderate and she has been in isolation since May 8 when her partner Clarke Gayford tested positive, it said.

Due to the positive RAT, Ardern will be required to isolate until the morning of May 21, and undertake what duties she can remotely this week.

Deputy Prime Minister Grant Robertson will address media in her place on Monday.

"This is a milestone week for the Government and I'm gutted I can't be there for it," Ardern said in the statement.

"Our emissions reduction plan sets the path to achieve our carbon zero goal and the budget addresses the long-term future and security of New Zealand's health system.

"But as I said earlier in the week isolating with COVID-19 is a very kiwi experience this year and my family is no different."