NZ Prime Minister Jacinda Ardern. [Photo: BBC News]

New Zealand Prime Minister Jacinda Ardern says the Queen told her she had to “just get on with it” when asked for advice about being both a leader and a new mother.

In 2018, Ms Ardern became only the second elected head of government to give birth while in office.

Speaking to the BBC, she also reiterated a belief that New Zealand would one day become a republic.

Ms Ardern is one of the hundreds of leaders in London ahead of the Queen’s funeral.

Appearing on the Sunday with Laura Kuenssberg programme, she was shown footage of her first meeting with the Queen, which took place when she was pregnant.

Asked about the conversation during that meeting, Ms Ardern said: “One of the things on my mind alongside being a new prime minister was being a prime minister and a mum.

“And when you think about leaders who have been in that position…, there were so few to look to.

“So I said to her, ‘How did you manage?’, and I remember she just said, ‘Well, you just get on with it’. And that was actually probably the best and most factual advice I could have.”

Prince Andrew and Prince Edward were both born after the Queen took the throne. The only other elected leader to give birth in office was Benazir Bhutto, who served as prime minister of Pakistan from 1988 to 1990 and 1993 to 1996.

Ms Ardern gave birth to daughter Neve Te Aroha in June 2018, returning to work in early August of that year.

Ms Ardern, who previously lived in London, said she hadn’t been surprised “at all” by the size of the public’s response to the Queen’s death.

“I’ve seen what London looks like day-to-day, and what it feels like day-to-day, the hustle and bustle,” she said.

“And to see it just stand still, but do so so poetically, is a very moving thing to witness. The Queen was here for her people, and now her people are there for her.”