Gareth Morgan claims there was no outrage when a woman used the same expression, "lipstick on a pig", to describe Labour's leadership change, days before he said it.
Public relations expert Trish Sherson used the reference on August 13, a week before the Opportunities Party leader used it in a tweet, it has emerged.
Speaking to Ryan Bridge on RadioLive's Sunday Brunch show - in audio that appears to have been removed from the site - Sherson said: "Here's a question though, and I think all voters need to consider this, when they think about the Jacinda effect, can you actually put lipstick on a pig and be successful? Let's not forget this."
She was asked "who's the pig" to which she replied: "I would say the left block at the moment is the pig."
She added: "I think she's a fantastic politician and very clever. But, the left is still in the same shambles, even worse shambles than when she took over. And Labour have still got the same dearth of policy and problems there."
"Voters have to look beyond 'Wow, we've got a woman and she is a real star, she's fantastic.' But if you look underneath Jacinda and this lovely, shiny gloss we've got on the left block, they are still in a state of absolute shambles."
Bridge said that to sum up the last 15 minutes of his interview with Sherson and politician Vernon Tava, "You can't just put lipstick on a pig and expect something to change. And the Greens should have been far more promiscuous from the start".