The threat of Donald Trump in the White House “scares the daylights” out of Australians and should prompt a rethink of the US alliance, says Greens Leader Richard Di Natale.

Asked if he agreed with Opposition Leader Bill Shorten’s comments that some of the presumptive Republican nominee’s policy positions were “barking mad”, Senator Di Natale said it was “a statement of the bleeding obvious”.

“He’s dangerous for the US and dangerous for the global community, and you just need to look at those clashes that we have seen recently between anti-Trump and pro-Trump supporters, huge division in the US at the moment.”

Violent scuffles and some attacks have become common at Mr Trump’s campaign events in recent months, and security is expected to be tight at next month’s Republican convention in Cleveland, Ohio.

Mr Trump secured the required number of convention delegates to seal the nomination last month.

Senator Di Natale restated his view that Australia should reconsider its strategic alliance with the United States and stop orientating its foreign policy around Washington.

“I think there’s no better time . . . to redefine the terms of the US alliance,” he said.

“We think it should be done . . . the fact that we are even talking about a Trump presidency scares the daylights out of most people.

“I think the first thing to do is look at the Australian national interest. I think it is absolutely in our national interest to redefine the terms of our alliance and not to commit troops blindly to international conflicts in the way we have done in the past.

“We are the only country that’s followed the US into every international conflict since World War II, including some major strategic blunders.

“I think the sign of a mature relationship is one where you can stand up to a partner and tell them when you think they have got it wrong. We haven’t done that, to our own detriment and the international community,” he said.

Senator Di Natale said a hung parliament after the July 2 election could be good for the nation.

Defending the Green’s agreement with Labor in 2010, he said the last hung parliament brought “the world’s best climate laws”, improved medical and dental care and a productive legislative process.

Campaigning last month, Mr Shorten said a Trump presidency would be “very difficult” for Australia and suggested Americans should instead vote for Democratic front-runner Hillary Clinton.

The comments drew criticism from the government and some commentators who said Mr Shorten risked insulting a possible US administration.