Simon Bridges says Prime Minister Jacinda Ardern was "stuck between a rock and a hard place" over reprimanding Health Minister David Clark after his breach of the Covid-19 lockdown rules.
The National leader added the reason the epidemic select committee, tasked with scrutinising the Government's response to the virus, did not ask Dr Clark any questions about his breach was because he did not want "to kick a man when he's down".
"At the end of Covid-19, the crisis we're in, I suspect he won't be a Minister. His position, more medium-term, is terminal," Mr Bridges said.
"You simply can't have Health Minister, one of the most important roles, (ranked) at number 20. For him, having a Prime Minister that doesn't have confidence in you will be fatal."
Earlier today, Ms Ardern stripped the Dunedin North MP from his Associate Finance portfolio and moved him down to the lowest ranking of Cabinet, saying under normal circumstances she would have sacked him.
Ms Ardern told media it would have been challenging to pull another MP up to Health Minister. "I was not willing to sacrifice the time to bring someone up to speed while we are in the midst of a global pandemic."
Mr Bridges said "the Prime Minister was between a rock and a hard place".
"To change Ministers right at the moment, I can understand why she wouldn't... saying that, I think the situation is one that is unsustainable for David Clark post-Covid-19".
Mr Bridges also rejected criticism of his travelling between Tauranga and Wellington during the lockdown, saying there was "no comparison".
"I'm going for work, I think essential work on Covid-19," he said.
He told Newstalk ZB his internet connection in Tauranga was "dodgy".