Prime Minister Jacinda Ardern and her partner Clarke Gayford are celebrating the birth of their first child.

Ms Ardern was admitted to the hospital on Thursday morning.

She confirmed the birth on Instagram, with a touching photo of her, Mr Gayford and her baby girl.

“Welcome to our village wee one,” she wrote.

“Feeling very lucky to have a healthy baby girl that arrived at 4.45pm weighing 3.31kg (7.3lb).

“Thank you so much for your best wishes and your kindness. We’re all doing really well thanks to the wonderful team at Auckland City Hospital.”

Deputy Prime Minister Winston Peters will step up to Acting Prime Minister while Ms Ardern is on maternity leave.

She has said she will take six weeks leave before returning to work running the country

Ms Ardern announced her pregnancy in January, just days after being sworn into office as the Prime Minister of New Zealand.

She had been the leader of the Labour Party for just three months at the time.