Paul Henry on his TV3 show this morning asked Lowe what he thought about the Labour MP's surge as preferred Prime Minister in the New Zealand Herald's latest DigiPoll.
He asked him if he thought, in the future, "we would be talking about" Ms Ardern as leader.
Mr Lowe said: "I'll tell you what, she's a pretty little thing at the moment. And what she says, she speaks pretty smart I think. She just comes across as the right image. It wouldn't surprise me in the future."
He said Prime Minister John Key also had a good "television image".
"If she was Prime Minister at some stage, she'd look good. You'd see her and you'd think 'Wow, she's our Prime Minister'."
TV3 presenter Hilary Barry tweeted after the incident: "Panelist describes @jacindaardern's skill in politics - 'she's a pretty little thing.' Rest assured he won't leave without bruised shins."
Ms Ardern responded with: "And for this, I thank you Hilary. I hope your shoes were pointy."
In the Herald DigiPoll, Labour frontbencher Ms Ardern is now the fourth preferred Prime Minister - behind Mr Key, Andrew Little and Winston Peters - at 3.9%, a jump from 0.5% in April.
National Council of Women chief executive Sue McCabe said the description of Ms Ardern as "a pretty little thing" was dismissive and condescending.
"Within the context, a woman's appearance is irrelevant; rather the focus should be on her abilities as a politician and potential prime minister.
"By focusing on her appearance and describing a grown woman as 'little', the panelist showed a lack of respect for Jacinda.
"This comment is sexist. Often when people highlight sexism, the concern is dismissed. More often than not, it's seen as a one-off comment and the person apologises.
"However, these comments are symbolic of the sexism that is entrenched in our culture.
"We call on New Zealanders to think about the language they use and make sure it reflects the equality of genders."
University of Auckland political studies senior lecturer Dr Anita Lacey said Lowe's remarks had been entirely dismissive and condescending.
"We would not describe a male politician in those terms ... focus on their looks," she said.
"It entirely undermines the work Jacinda has done as a politician and her achievements. It's not just commenting on her looks, but it's done in a condescending way that she can be dismissed as a bit of eye candy.
"He is not saying she is a beautiful woman; only that she is a pretty little thing. So she is not even a woman. She is a thing. Completely objectified."
In reply to the criticism, Mr Lowe, aged 69, said: " I was trying to compliment her. I come from an era where calling someone pretty was one of the highest compliment and so I did.
"I would worry about offending Jacinda herself, and If I did I apologise.
"But I was giving her a compliment on her image and just how powerful she comes across.
"She is the full package. She is smart and compelling to watch and listen to."
