Kelvin Davis says Bill English has "the personality of a rock", but the Prime Minister's choosing to take it as a compliment.
"I'm a Hollywood star, that's me," he told The AM Show on Monday, referring to action star Dwayne 'The Rock' Johnson.
"I'm getting hundreds of selfies every day, big crowds, it's all working well."
Mr Davis had been Labour deputy leader only five days when he launched an extraordinary attack on National.
"If we look over the side there we see a Prime Minister with the personality of a rock," he told TVNZ.
"We've got the Jacinda effect and then we've got Paula Bennett, who's mastered the Lynn of Tawa effect.
"We've got Jonathan Coleman, the doctor of death, we've got Steven Joyce, who's as authentic as a $4 Rolex, we've got Gerry Brownlee, who's got the energy of a small hill, we've got Simon Bridges, the only person under 80 who still buys Bryl, and we've got Judith Collins - look, her stare caused that ice shelf in Antarctica to crack off and float away."
Mr English says the Te Tai Tokerau MP needs to up his shade game.
"If he's meant to be throwing around insults, it's not that good, is it? The positivity didn't last very long, but we're not too worried about whatever he's said."
The National Party account ran with the 'rock' idea on Twitter, saying Mr English is a "rock [that] got us through the global financial crisis and back into surplus".
The 'rock' vs 'The Rock
- Twitter followers: The Rock: 11.6 million, Bill English: 21,000.
- Facebook fans: The Rock: 58 million, Bill English: 100,370.
- Instagram followers: The Rock: 91.3 million, Bill English: 2,711.
- Google results: The Rock: 12.2 million, Bill English: 454,000.