'Both sides' to blame for partisan breakdown in US politics - Todd Muller

New National Party leader Todd Muller says "both sides" are to blame for the fracturing of American politics, as he faces criticism for owning a Donald Trump signature 'MAGA' hat.

A profile on Muller published by The Spinoff in September last year included a photo of souvenirs he picked up while in the US in 2016 - including one of the red 'Make America Great Again' hats. 

There's been criticism on social media that the hats symbolise white nationalism and other negative traits associated with the Trump administration.

"I have that portrait of Adolf Hitler because I'm a history buff," one critic posted on Twitter. "No one ever mentions my Churchill bust!"

Since becoming National leader, Muller has insisted the hat is just representative of his interest in American politics.

Muller told Newshub Nation on Saturday he also picked up a Hillary Clinton badge which "never gets looked at".

"Everyone sees the MAGA cap and somehow reaches a conclusion that perhaps is where my sympathies lie."

Asked on Magic Talk's Sunday Cafe show what he thought of Trump, Muller said he was making the US a more politically divided place.

But he said Trump's rivals, the Democrats, are also to blame.

"Over the last 30 or 40 years it's become more and more partisan, and I think that doesn't work for the country as a whole. This is not an anti-Republican or anti-Democrat - I think both sides have built that partisanship to the level that it appears from the outside to be becoming quite destructive."

Muller has previously spoken of his interest in US politics and as a child, wanted to one day become President - an unachievable goal, as he was not born on American soil. He said it's a shame what's happened since then.

"The great strength of the American system is you used to have these lions of the Senate, they were called, who would always cut the deal in the middle to make the thing actually work, and find a compromise that can endure... I have seen over successive Presidents things getting more partisan." 

On Saturday when asked whether he backs Joe Biden or Trump to win this November's election, he would only say that after seeing them both deliver speeches in 2016, Biden was the better orator.