Tukituki MP Lawrence Yule says rolled National leader Simon Bridges couldn't connect with the public. Photo / Paul Taylor
Yule described Muller as a "stunning individual, very capable and empathetic".
"Bridges was incredibly hard-working, with a young family, and was so dedicated," he said.
"But some people have a connection with the public and some people don't. And unfortunately, in the final analysis, I think that is what forced the change.
"He's not a bad person but the negative reception was the thing that led to the change."
Yule's position in Tukituki could be precarious if National's slide with the public continues and he said he'd be campaigning hard on the election trail.
"A lot of money is being borrowed in the post Covid-19 response. I'm not against borrowing money but I want to make sure it is properly delivered and targeted to get results," he said.
"The Labour Government has been very poor with its record of delivering on its promises – looking at KiwiRail, light rail in Auckland and a whole lot of others."
"We've also got the biggest borrowing programme since World War II and I want to make sure Hawke's Bay gets a share of the resources and that money is being appropriately spent."
Bay of Plenty MP Muller will likely lead National in the election on September 19, unless there is another leadership challenge, with Auckland MP Nikki Kaye elected his deputy, replacing Paula Bennett.