New Zealand’s leader Jacinda Ardern has announced she will be “prime minister and mum”, revealing she is pregnant with her first child and learnt the news just days before she became prime minister-elect following her surprising election result last year.

Describing her partner Clarke Gayford as the future “'first man of fishing' and stay at home dad”, Ms Ardern said the baby, due in June, was unexpected and they had been told by doctors that she could not become pregnant without “help”.

She is set to become only the second leader in modern times to give birth in office after Benazir Bhutto, Pakistan’s prime minister, whose daughter Bakhtawar was born in 1990.