Todd Muller pleads for questions on $1.5b highway after interrogation over National MP Hamish Walker

National Party leader Todd Muller begged reporters to ask questions about his newly-announced proposed highway in Canterbury after he was interrogated about a rogue MP in his party.

Muller began a press conference on Wednesday talking about National MP Hamish Walker, who had resigned earlier in the day after admitting on Tuesday evening to leaking confidential data about COVID-19-positive patients in New Zealand quarantine facilities.

Muller then spent the following nine minutes answering questions about the leak, saying he'd lost confidence in Walker and he'd made a "serious error of judgement" in forwarding the patients' information to media outlets.

But appearing to also want to talk about his expressway announcement, he pleaded with reporters to ask questions about this too.

"Any questions about the road? Come on, $1.5 billion, four-lane highway, fantastic," he said.

One journalist asks him about the new highway, which put a smile on his face and he said: "Oh here we go."

The proposed 60 kilometre-long expressway would stretch from Christchurch to Ashburton. Development would begin during National's first term if the party was elected this election, with construction likely to start after 2023. The cost of the project is estimated to be $1.5 billion.

Muller estimated "hundreds of jobs" will be created during construction and it will be a "significant investment" in the local economy.

"The project will create important economic stimulus and jobs in the short-term while also allowing Canterbury to maximise its future economic potential," he said.

"State Highway 1 is the major economic corridor for the movement of freight and commercial activity in the South Island. If we want our economy to create jobs, having an efficient transport network is essential."

National MP Andrew Falloon, who represents the Rangitata electorate in Canterbury and is also the party's transport spokesperson, said he's "thrilled" about the proposed highway.

"It's one of the most dangerous roads in the country in terms of fatalities and serious injuries, so it's wonderful we're finally getting on and getting started with it."