SARAH FERGUSON, PRESENTER: Ever wondered why political parties like the Motoring Enthusiast Party and Sports Party did so well at the last election? The answer is one man, the so-called "preference whisperer", Glenn Druery. He's been wheeling and dealing behind the scenes in elections, tying up preference deals with minor parties for years and will do so again at this weekend's Senate election in Western Australia.

In the wake of last year's results from the Senate election, which saw some people winning on primary votes of less than half a per cent, the Government is planning to reform election laws. But what role has Druery played and is he an honest broker?

Dylan Welch reports.

DYLAN WELCH, REPORTER: Nimbin solicitor and marijuana enthusiast James Moylan could be a senator come July.

JAMES MOYLAN, MARIJUANA ENTHUSIAST: Cannabis will be legal in Australia. Right? We have the option of doing it in a rational manner and learning from the mistakes of overseas.

DYLAN WELCH: James Moylan is standing for the HEMP Party in Saturday's Senate re-run election in WA. If he succeeds, as some election experts have predicted, it'll be on a primary vote of less than 1.5 per cent and with just one aim: to legalise marijuana use.

Moylan's campaign is being organised by the HEMP Party's registered officer, Graham Askey, and if he wins, it will be due to Askey's hard work securing preference deals with dozens of other minor parties.

GRAHAM ASKEY, NATIONAL SECRETARY, HEMP PARTY: Elect a hippie from Nimbin into the Australian Senate - that is my dearest wish.

DYLAN WELCH: Another man is also playing a key role in HEMP's rise, the so-called "preference whisperer", Glenn Druery. Druery is not your average political player. His unorthodox approach to Senate elections has won him admirers, who say he is bringing power to the people, and critics, who believe he's been gaming the system for years.

GEORGE WILLIAMS, CONSTITUTIONAL LAW, ANU: I think what Glenn Druery is done is two-fold: he's recognised a weakness in the system and he's good at maths. He's realised how that system can be exploited and he's entitled to do so. The system is designed in a way that enables that to happen.

DYLAN WELCH: Druery's first real tilt at politics was in New South Wales in 1999 when he ran as the founder and lead candidate of the Republic 2001/People First Party.

GLENN DRUERY, CANDIDATE, REPUBLIC 2001/PEOPLE FIRST PARTY (1999): Look, I'm an ordinary bloke that grew up in the Western Suburbs of Sydney and I left school and I did a trade as a carpenter. I've decided to have a go at the political sphere and see what happens. ... I decided to put a group together. I rang 40 to 50 small parties and we met.

DYLAN WELCH: The election included 80 parties and a ballot paper so large, it was nicknamed the "Tablecloth" ballot. What voters wrestling with the "Tablecloth" ballot didn't know was that at least 21 of those 80 parties were fronts created by Druery to harvest preferences.

GRAHAM ASKEY: A front party is a party that, um, is created with an attractive-sounding name and is actually controlled by another person. And then the idea is then that that front party will automatically give a second preference to the party that has created it.

DYLAN WELCH: In 1999, the HEMP Party's Graham Askey, himself a talented preference negotiator, have first-hand experience of Druery's machinations.

GRAHAM ASKEY: I didn't actually approve of creating front parties, but I had a sneaking admiration for his cleverness.

DYLAN WELCH: Druery failed to win a seat, but the use of fronts and preference manipulation led to reform of the state's electoral law. The changes pushed Druery towards national elections, where the law hadn't changed since the 1980s. In 2007, he joined David Leyonhjelm's Liberal Democrats.

DAVID LEYONHJELM, SENATOR-ELECT, LIBERAL DEMOCRATIC PARTY: We used to describe him as a value-free zone. He wasn't - we're a libertarian party or classical liberal party. When we used to ask him, "Well, what do you actually believe in, Glenn?," the answer was very vague. He would be very hard to be pinned down.

DYLAN WELCH: David Leyonhjelm won a Senate seat for the LDP at last year's election with about 9.5 per cent of the primary vote and a complex preferencing arrangement based on skills he learnt from Druery.

DAVID LEYONHJELM: Where Glenn Druery is very skilled is in understanding how those preferences, if they are allocated, what the impact of them will be on the outcome. And if you put them in a certain order and you get them coming before another party who's knocked out, you will end up benefitting.

DYLAN WELCH: Druery's ruthless tactics have led to a series of fallings out with minor parties. He fell out with the LDP after missing out on a Senate seat in 2010, for which he blamed David Leyonhjelm.

DAVID LEYONHJELM: I don't think he's made much study of political philosophy or understanding ideology or anything like that. So it comes naturally to him that if you want to get elected, you do what it takes to get elected.

DYLAN WELCH: It was in 2013 that Druery truly burst onto the national stage with his minor party alliance, an unlikely gathering of two dozen left and right-wing groups that included the Sex Party, the Australian Christians, One Nation and WikiLeaks.

GREG BARNS, FORMER WIKILEAKS PARTY ADVISOR: What he taps into is the fact that - the drug of politics that people want to get elected. The first meeting I ever went to with him, he said something to the effect of - there were about 20 or 30 people in the room - "One of you and your party will be elected." And he had them from that moment on.

DYLAN WELCH: The WikiLeaks Party left the alliance after choosing not to preference as per Druery's advice.

GREG BARNS: Well I think he said to me, "You're finished," you know, "And I can't believe you're doing this," or words to that effect. And I said, "Well, Glenn, look, I'm sorry, but this is what the party has - the party council has indicated that I need to do." I was effectively, you know, the bearer of bad tidings. And so he was - he didn't raise his voice, but he was decidedly hostile.

DYLAN WELCH: Leyonhjelm also earned Druery's ire when the LDP chose not to preference the Shooters and Fishers Party highly last year.

DAVID LEYONHJELM: He rang and left a message on my voicemail on my mobile saying, "You're politically dead. I will make sure that you never succeed in politics. This is my life's mission, to achieve that." So, he was very serious about it.

GLENN DRUERY (2013): I think we've got to ask ourselves this question is: what type of political system do we want in this country?

DYLAN WELCH: Another issue raised by alliance members was: who was paying Druery? He declared he was being paid by the Shooters and Fishers Party, but rumours of other backers remained.

GRAHAM ASKEY: At all of the meetings in 2013, he always started by announcing that his client was the Shooters and Fishers Party. And he also started, "As far as I'm concerned, I'm extremely pragmatic. This is - to me, each of you small parties just are a number."

DYLAN WELCH: 7.30 has learned Druery was also being paid by Family First in Victoria and the Fishing and Lifestyle Party in Queensland about $5,000 a month each for up to six months.

I have been told he was also paid by Family First and by the Fishing and Lifestyle Party. Does that raise any issues for you?

GRAHAM ASKEY: No, I think that would create something of a conflict of interest, yes.

DYLAN WELCH: So what's your view then, as a member of the minor party alliance?

GRAHAM ASKEY: I don't think it's wise to try and ride more than one horse at a time.

DYLAN WELCH: Druery also offered to pay for the nomination fees of several parties associated with the LDP if they agreed to let him manage preferences.

DAVID LEYONHJELM: What we were more bothered by was how controlling it was attempting to be. That, "If you do it our way, there are benefits. If you don't do it our way, we'll hurt you."

DYLAN WELCH: A parliamentary inquiry was called last year following the election on a tiny primary vote of senators from two parties within the alliance, the Motoring Enthusiasts Party and the Sports Party. Earlier this month, the inquiry held a public hearing in Sydney.

GEORGE WILLIAMS: It does create a lottery-like effect where it's quite possible for microparties to aggregate preferences in a way that gives one of them a realistic chance of being elected, and that's happened, of course, in this last election.

DYLAN WELCH: 7.30 has been told the inquiry will recommend changes to electoral law in order to prevent the microparties using preference trading to guarantee Senate seats.

Such a move may not end Glenn Druery's involvement in national politics, with rumours he is planning to become a staffer in the office the Motoring Enthusiast Party's Ricky Muir when the Victorian moves to the Senate in July.

SARAH FERGUSON: Glenn Druery declined to answer questions or be interviewed by 7.30 for this story.

Dylan Welch with that report, produced by Nikki Tugwell.