Judith Collins says if Jacinda Ardern needs a day off being Prime Minister, she should take it.
The Prime Minister returned to her day job on Thursday, after six weeks' maternity leave spent at home with baby Neve and partner Clarke Gayford.
Labour MP Peeni Henare told The AM Show on Friday she'll be "straight back into her stride".
"It will be a challenge with a baby, but we have other MPs with babies and they tend to get on with business as usual."
But as Ms Collins points out, not all MPs have the same level of responsibility as the Prime Minister.
"My advice to her is if she has to have a day off, have a day off. You're spending all your time focused on this little baby - and by the way, they never do what they're told, never ever ever, and they do not stop."
Ms Collins, appearing alongside Mr Henare, said the Opposition wouldn't criticise Ms Ardern if she took a day off, as they know what it's like to be parents.
"It's tough as we know with kids, but I think it'll probably make her a better politician, because you just understand what people go through. We understand tiredness, we understand how hard it is to juggle everything together. Being a parent is a huge job."
Mr Henare said he spoke to Ms Ardern a lot while she was on leave, and Ms Collins is right.
"Just like a normal human being - I asked how she is and she says, 'I'm tired,' and rightly so. That's what you'd expect."
With Ms Ardern back at work, Mr Gayford - a TV fishing show host - is now a full-time stay-at-home dad. Perhaps taking advantage of the break from having to present his show, he's grown a beard.
"I'm not immune to the chatter and I feel I need to front foot the fact that yes; I've grown a beard, to fit in, in Wellington," he wrote on Twitter.
"Feel free to drop pin me good craft beer locations, I want the whole experience."
Winston 'didn't do anything particularly exciting'
Mr Henare said Winston Peters' stint as Acting Prime Minister strengthened the Government by showing it was a real coalition, not just the Labour Party.
"I think the coalition's in a better place after this leadership by Winston. We can now get Jacinda Ardern back. We're in a better position, I really feel that... We managed well, I think. Nothing was off the table - everything was business as usual - and I think he proved that he could do a pretty good job."
Ms Collins said Mr Peters' tenure was only notable for clearing a "very low bar".
"People I felt think, at least he didn't destroy any industries when he was in there. He didn't do anything particularly exciting, apart from occasionally call people names. It was a bit mean."
Host Duncan Garner pointed out at the National Party conference last weekend, party president Peter Goodfellow called Mr Peters a "whisky-swilling, cigarette-smoking, double-breasted and irrational bullet".
Ms Collins said he would have enjoyed being spoken about, and jokes about Mr Peters "always get a laugh".