Coronavirus: Prime Minister Jacinda Ardern forced into isolation after partner Clarke Gayford tests positive for COVID-19

Prime Minister Jacinda Ardern has been forced into isolation after her fiancé Clarke Gayford tested positive for COVID-19.

Ardern announced the news on her Facebook page on Sunday morning, saying Gayford was infected but she and daughter Neve were "fine".

"Happy Mother's Day everyone! It's not even midday and already I’d say ours has been a mixed bag," she wrote.

"Neve was so excited that it was Mother's Day, she got up nice and early to share this lovely card!

"The downside is Clarke woke up feeling a bit average and has tested positive for COVID, so we have seven days of family time ahead of us!

"I'll be working from home so anyone who watches question time, or is attending my Business NZ speech on Wednesday, you'll still see me remotely!

"Otherwise, a happy Mother’s Day to everyone who plays mum in anyone's life."

This is the second time Ardern has been forced into isolation this year after being deemed close contact with a positive case in January.

Ardern and Governor-General Dame Cindy Kiro were in Northland for a prerecording for Waitangi Day. They were exposed during flight NZ8273 from Kerikeri to Auckland on Saturday, January 22.

Those close contact rules have since been scrapped and only people in the same households as positive COVID-19 cases have to isolate for seven days.