Mark Richardson slams The National Party, says Todd Muller has 'failed every time he's stood in front of the media'

Despite The National Party being in a new era, Mark Richardson has lashed out at new leader Todd Muller saying he's "failed every time he's stood in front of the media".

After Muller appeared on The AM Show on Wednesday, sports reader Richardson said the new leader had to take the opportunity to "stand up" after a disastrous day in Parliament on Tuesday.

In defending claims National had a lack of diversity in its top 12, Muller and deputy leader Nikki Kaye wrongly identified Pākehā MP Paul Goldsmith, the party's finance spokesperson, as Māori.

Muller also backtracked after earlier saying he'd display his "Make America Great Again" hat in his new office. He told reporters on Tuesday he's now packed it away after the controversy surrounding the cap, which was used by US President Donald Trump in his 2016 election campaign.

But Richardson said Muller should have dismissed both those issues.

"Well done Ryan - you had to push Muller this morning," Richardson told host Ryan Bridge after the interview. "You had to push him because he had to take an opportunity to stand up and be pushed, and come back well and be clear and concise.

"That is something that The National Party faithful have been praying for in a leader and so far, apart from the pre-prepared speeches that he's given in Parliament that have been good, he has failed every time he's stood in front of the media and I am pissed off."

Richardson said the "rubbish" debate around the cap should have been dismissed.

"He [Muller] should not have buckled on the Trump hat. He should have said, 'that is a ridiculous argument, I don't want to hear it again'.

"They [National] have not come up with at least two decent points and policies - saying 'this is what we'd have done differently'. As a National supporter, that is totally and utterly unacceptable and those National Party members who are now undermining him, get over yourselves, stop sulking, and start representing this country."

During his interview with The AM Show earlier, Muller said the success of Māoridom was "absolutely critical" to New Zealand.

"National has a fantastic record over the years as being the party that actually delivers outcomes for Māori."

Asked by Bridge why there were no Māori MPs on its front bench Muller said, "I look at it through the lens of a Cabinet. I've got a shadow Cabinet of 20 and I have Paula Bennett and Dr Shane Reti in that shadow Cabinet".