Why Mark Richardson isn't celebrating Jacinda Ardern's first month as PM

Shots have been fired between Mark Richardson and Prime Minister Jacinda Ardern again, although this time it's unlikely to make world headlines.

On Monday morning, The AM Show host Duncan Garner asked Mr Richardson whether he brought in a cake to celebrate Ms Ardern's first month in the job.

When Richardson responded with silence, Ms Ardern answered, "He doesn't seem like the celebratory type in that regard."

Ms Ardern traded shots with Richardson back in August, when Richardson argued employers - and in Ms Ardern's case the New Zealand public - needed to know whether women are planning on having babies.

The exchange made headlines around the world, but on Monday morning things were much more lighthearted, with Richardson joking that the Prime Minister was calling him a "sad sack."

After stating she'd love to be proved wrong, Ms Ardern asked Mark whether he was, in fact, the celebratory type.

"When there's something to celebrate Jacinda, I'll celebrate it," Mark grinned.

The Prime Minister laughed, saying that answer was "a bit harsh". 

"He doesn't want to celebrate my month in the job! Let's make it twelve months then."

Mark agreed to celebrate the one year anniversary of Ms Ardern's appointment as Prime Minister.

"I'll bring in some tic-tacs."

Newshub.