Best known for statements linking same-sex marriage to bestiality, the Liberal senator has recently proven he can be effective as well as outrageous.

Months before Kevin Rudd had announced his candidacy to lead the United Nations, Bernardi insisted the Turnbull government should not nominate such a "dysfunctional", "vengeful", "unstable" figure for the post.

His view won the day - not Foreign Minister Julie Bishop's argument that Rudd deserved a shot.

Then, on the first sitting day of Parliament, Bernardi convinced all but one of his colleagues on the Senate backbench to sign a petition supporting changes to the Racial Discrimination Act. Accused by Labor of operating in "open defiance" of his leader, Bernardi had achieved what he wanted: the issue was back into the headlines.

And when Labor senator Sam Dastyari was caught out invoicing a Chinese donor for his travel expenses, Bernardi was first off the blocks to attack him. Speaking under parliamentary privilege, Bernardi said the affair had a "stench of corruption" and wondered if Dastyari was Labor's "Manchurian candidate". It was a sharper line of attack than most cabinet ministers have mustered.

His GetUp!-style conservative lobby group has also signed up over 50,000 members.

Now he's about to go global.

Next week Bernardi will fly to New York for a three-month secondment at the United Nations.

As well as the UN's climate change and economic work, the seasoned culture warrior says he is keen to learn about peacekeeping operations. The UN's Special Committee on Decolonisation has also caught his eye.

In the past, Bernardi has been a fierce critic of the UN, describing it as a "fiscal black hole of bureaucracy" and an "unelected and unaccountable body".

"This is a huge opportunity to broaden my horizons," he says.

"I have thought the UN is expensive, inefficient, bureaucratic and exerts too much control over our domestic affairs.

"I'm interested to see if my perceptions are accurate or not."

His trip coincides with the US election, which will allow Bernardi to experience the Donald Trump phenomenon up close. He believes the rise of Trump reflects a deep distrust in conventional politics spreading around the world.

The UN secondments are available every two years, with one spot reserved for the Coalition and one for Labor.

The politicians from each party decide among themselves who gets to go. Bernardi has been knocked back before and says this year's vote was "hotly contested".

A key part of his pitch, he jokes, was that those colleagues who dislike him could get rid of him for three months by supporting him.

Fellow South Australian Christopher Pyne will be one of those happy to see him out of the country. Pyne, a leading moderate, and Bernardi famously loathe each other.

Asked on the weekend whether he had undermined the Coalition with his 18C push, Bernardi said: "I'm not going to suspend what's important to the Liberal Party in favour of those people who can't even control the Liberal Party in the lower house." It was a blatant dig at Pyne, the government's Leader in the House of Representatives.

Travelling with Bernardi to the UN is his political polar opposite: Tasmanian Labor senator Lisa Singh.

Bernardi - who is anti-abortion, gay marriage and a climate sceptic - is on the right of his party. Singh is one of Labor's most left-wing MPs.

Bernardi is aware he will be representing Australia so he won't be "freelancing" on policy at the UN.

But he will continue sending out regular email editorials to his 75,000 subscribers and monitoring politics at home. He wants to make sure the question for any plebiscite on same-sex marriage is not "stacked" against opponents by including terms such as "marriage equality" as Labor leader Bill Shorten would like.

"I'm not going to suspend my interest in domestic politics," he says. No matter how much his political opponents, and his own colleagues, may want him to.