Interview: Jacinda Ardern and partner Clarke Gayford sit down to discuss their pregnancy

To say that Prime Minister Jacinda Ardern and partner Clarke Gayford are excited about their pregnancy would be an understatement.

The proud parents-to-be shared how they were always motivated to have a family and wanted to make sure New Zealand was the best country in the world to be a child.

"How great it would be for us all to have the pride of knowing that we as a country are one of the best countries to be a child," Ardern said in an exclusive sit down with NZ Herald Focus.

She said that it has always been a goal and what Labour's families package and poverty bill was all about.

The pair added that they sat down together to decide who would look after the baby once it was born.

"We debated roles and we looked at the various pros and cons … It was always going to be me," Clarke said.

The pair will have to be careful what they say over the coming months with Ardern admitting she didn't want to reveal the gender of the baby until it was born.

"We're trying around each other not to use gender language in case that means we go out and let it slip because it's the one thing we are trying to keep a surprise."