During a fierce late-night debate in Australia's Parliament earlier this year, officials in the chamber found themselves confronted by an unusual sight: an MP had turned up in his pyjamas.

It came as little surprise to find that the MP was Nick Xenophon, an independent from South Australia who has become known for his headline-grabbing political stunts, often involving costumes or animals such as giraffes and goats.

Mr Xenophon, who was angry at the government's attempt to quickly pass its changes to voting rules, later admitted he merely "wanted to make a point". He changed into a suit and returned to the Senate chamber to re-join the debate.

But this mix of unpretentious humour and no-nonsense practicality has helped to boost his popularity and turned him into a potential big winner of the coming election on July 2.

With the ruling Coalition and Labor both floundering in the current campaign, opinion surveys suggest that Mr Xenophon - something of an anti-politician - could benefit from a potential drift away from the main parties.

Surveys suggest his new party, The Nick Xenophon Team (NXT), could win three seats, including his own, in the Senate, or Upper House. The party could also win a House of Representatives, or Lower House, seat - all in his home state of South Australia.

Analysts believe this could be enough to hand his party the balance of power in the Senate.

"South Australia has suddenly become important to the nation because success for the Nick Xenophon Team at this year's double dissolution will deliver it a powerful position in the Senate, and potentially a say in a finely divided House of Representatives," election analyst Antony Green told ABC News. In a double dissolution, all the Senate seats are also up for grabs.

Aside from his stunts - or perhaps because of them - Mr Xenophon, 57, is known for his crusades against gambling and casinos and his campaign to protect jobs and local industries from foreign competition.

A child of Greek immigrants to Adelaide, the former personal injury lawyer, drives a cheap, battered car, flies in economy class and is said to work "100-hour weeks". He has a child from a marriage which ended but reportedly remains close to both his son and ex-wife.

He is a vocal critic of Australia's free trade agreements and has opposed the control that Australia's supermarket duopoly, Coles and Woolworths, has over the local market. He is socially liberal and supports same-sex marriage and an emissions trading scheme to combat climate change.

The rising popularity of NXT has worried the ruling Coalition and prompted former Prime Minister John Howard to travel this week to South Australia to campaign for local Liberal candidates.

Mr Howard has likened Mr Xenophon's rise to that of unpredictable populists such as Donald Trump in the United States and Australia's right-wing firebrand Pauline Hanson.

"Some of the issues that Pauline Hanson talked about, Nick Xenophon has talked about - certainly trying to whip up concern about free trade agreements," Mr Howard told an Adelaide radio station.

In typical fashion, Mr Xenophon welcomed the attention from Mr Howard and embraced being labelled a "protectionist".

"If standing up for Australian manufacturing industry and the jobs of Australian workers is protectionist, then that's a badge of honour I'll happily wear," he wrote in a column in The Australian Financial Review on June 9.

Associate Professor Haydon Manning, an expert on Australian politics at South Australia's Flinders University, said Mr Xenophon has successfully won a reputation as "the little guy battling for the poor fellow of South Australia". Surveys suggest the NXT party is on track to receive 22 per cent of votes in the state.

"He's a 'small-l' liberal - an economic nationalist with a populist streak," he told The Straits Times.

According to the latest Newspoll survey, published on June 6, support for the larger parties - the Coalition, Labor, the Nationals and the Greens - has been dropping during the campaign.

A record 15 per cent of voters say they will vote for a small party or independent candidate.

Only 37 per cent of voters are satisfied with Prime Minister Malcolm Turnbull and just 33 per cent with his rival Bill Shorten.