Winston Peters has no chance of being a part-time prime minister should NZ First end up in coalition with Labour or National.
He hasn't said he would demand job-sharing if he held the balance of power after the next election, but didn't directly answer the question when it was put to him on TV3's The Nation at the weekend.
"It's immaterial unless we get the kind of sign-up and support that we are seeking in 2017," he said.
That raised questions at Prime Minister John Key's post-cabinet press conference.
"No chance," said Mr Key.
"It's just not going to happen... it would be totally unacceptable to the New Zealand public, it's a joke."
Labour leader Andrew Little had already ruled it out, saying under his watch the prime minister's job wouldn't be up for grabs.