Sean Plunket says he'll join Duncan Garner going vegan if Donald Trump wins US election

Sean Plunket says he'll join Duncan Garner going vegan for a year if Donald Trump wins a second term at next month's Presidential election.

The AM Show host Garner in July promised he would turn vegan if Labour polled high enough to govern alone - something the party did on Saturday night, winning the election in a landslide with 64 seats.

Now another broadcaster is jumping on the vegan bandwagon. During his Magic Talk radio show on Tuesday, Plunket was adamant Joe Biden would beat Trump in the US election.

"I've decided to make my own political pledge, and that is; if Donald Trump wins another term as US President, I will join Duncan Garner in going vegan for a year," Plunket told listeners.

"If not, I will keep a very close eye on Duncan."

Garner joked on The AM Show that Plunket's pledge was "gutless".

"Trump's in trouble - all the polls indicate he's in trouble," Garner said on Wednesday.

Newsreader Amanda Gillies said she backed Plunket over Garner to complete the diet.

"I'm a realist; I know you, I know you love your meat," she told Garner. "[But] I want you to do it, and I know how stubborn you are, and I know you actually do want to do this, so you have my full support."

On Monday, senior Labour MP Grant Robertson said he'd also consider going vegan if Garner kept his promise.

"Maybe I'll have to think about it," he told Garner. "I'll need you to lead the way on that." 

On Tuesday morning's show, Garner said he would stick to his word.