LEIGH SALES: This year's election made it clear that the conservative vote in Australia is up for grabs, so it's no wonder politicians are clamouring to secure it.

Rumours continue to swirl that Liberal Senator Cory Bernardi will start his own party appealing to voters on the right, a space that at the moment is filled by Pauline Hanson's One Nation.

For its entire history, One Nation has struggled with internal discipline and already just a matter of months after the federal election, a bitter power struggle within the party is threatening to rage out of control. Two former candidates are joining the party's ousted treasurer in publicly slamming the way One Nation is run and as Peter McCutcheon reports, much of the criticism is levelled at one of Pauline Hanson's closest advisers.

CROWD: Pauline! Pauline! Pauline!

(CHEERING)

PETER MCCUTCHEON, REPORTER: The remarkable resurgence of Pauline Hanson's One Nation has gone hand-in-hand with the political resurrection of a controversial staffer.

JAMES ASHBY, ADVISOR: I never anticipated, ever coming back to politics.

PETER MCCUTCHEON: James Ashby in 2012 accused his employer and parliamentary speaker Peter Slipper of sex harassment - has been Senator Hanson's close confident confidante and political adviser for the past 18 months.

PAULINE HANSON: This guy, he's the guy that actually has helped me.

PETER MCCUTCHEON: He's helped deliver electorate success at the expense of making enemies.

IAN NELSON, FORMER ONE NATION TREASURER: He intimidate, bullies everyone using Pauline as his political stick. He is in her head and she needs to get him out of it.

All you do is take off the hose...

PETER MCCUTCHEON: For the past 20 years, Ian Nelson has taken time off his motor business to volunteer for One Nation before being effectively sacked as party treasurer in August.

And now the One Nation founding member is speaking out against what he sees as James Ashby's malevolent influence.

IAN NELSON: He's just a little control freak.

PETER MCCUTCHEON: But what does it say about Pauline Hanson's ability to lead a party if she is, as you argue, so easily led astray by James Ashby?

IAN NELSON: Yeah, it took time for him to do that, but I'm concerned.

She is not the person that she was before. She is not a leader right now, she is just completely being controlled by Ashby.

PETER MCCUTCHEON: His concerns about James Ashby are echoed by former federal candidates in this year's election.

GEOFF VIRGO, FORMER ONE NATION CANDIDATE: I realised fairly quickly he had ultimate power because Pauline didn't ring. If you wanted to ring Pauline he answered the phone. If you wanted to email Pauline, he replied to the emails so she had literally been cut off.

MICHELLE PEDERSEN, FORMER ONE NATION CANDIDATE: There is no way that I would have him anywhere near me at such a crucial time, I think it was just a silly decision, I don't think he brought anything extra to the party that would negate those negative issues that he brought with him.

PAULINE HANSON: We've polled the third highest of all the political parties...

PETER MCCUTCHEON: 7.30 caught up with One Nation in happier days, just after the July 2 election, in which the party had defied expectations and secured four Senate seats.

JAMES ASHBY: You just don't deal with it, it's that simple.

PETER MCCUTCHEON: But behind the scenes the former party treasurer claims James Ashby was already causing trouble.

IAN NELSON: The first thing he did was he alienated Pauline from everybody - from everybody.

And when she came into her office one day I said, you know, this little fellow has alienated you from your entire support group and she actually looked at me and said, "What support group?". I couldn't believe it. She just has lost the plot.

PETER MCCUTCHEON: On Sunday, when Pauline Hanson announced her 36 candidates to run in the next Queensland election, Ian Nelson had been out of the party for four months and had agreed to keep quiet.

PHOTOGRAPHER: Alright, you lot in the back!

(CHEERING)

PETER MCCUTCHEON: But the former treasurer changed his mind when he discovered the candidates were each being told to buy $3,500 worth of campaign material from the party, which is supplied by a printing company controlled by James Ashby.

IAN NELSON: Well, it's morally wrong when you can do it for a thousand less. I don't know who does his printing but he certainly doesn't do it, he's just a middle man at the moment, he's getting other people to do it. And while all this is going on he is supposed to be a full-time staffer for Federal Parliament, so where on earth is he getting the time to do it?

PETER MCCUTCHEON: James Ashby declined 7.30's request for an interview but in a statement said his printing company wouldn't be the the party's only supplier and was providing good value.

STATEMENT BY JAMES ASHBY: My corflute cost was $8 per sign, that's all the party was charged. Sadly Ian Nelson is a very bitter and spiteful former executive party member.

PETER MCCUTCHEON: He also questioned the former treasurer's ability to do the job:

STATEMENT BY JAMES ASHBY: He was brought to task by the executive numerous times, once crying and apologising profusely in front of the whole executive for a horrible attack on myself and Pauline.

PETER MCCUTCHEON: Ian Nelson denies this, and he isn't the only One Nation dissident who is concerned about James Ashby and his printing services.

GEOFF VIRGO: I did think at the time it was a bit of a conflict of interest, to be honest.

PETER MCCUTCHEON: Geoff Virgo says he was asked to buy $1,000 worth of material from James Ashby when he contested the Townsville seat of Herbert in last July's federal election.

GEOFF VIRGO: Where I found it alarming was that nothing was delivered at all. On time. And some of it was delivered the week of the election.

PETER MCCUTCHEON: The other former One Nation identity who is understood to have had a falling out with James Ashby is Western Australia Senator Rod Culleton, who resigned from the party three days ago after weeks of instability.

PAULINE HANSON: Rod, excuse me, I'm party leader - I expect you to come to my office.

PETER MCCUTCHEON: And Ian Nelson says it is this saga that ultimately prompted him to speak out.

IAN NELSON: What they did with Senator Culleton was absolutely reprehensible, absolutely unacceptable, for a leader to do that.

And then, of course, bag him - publicly. And I can tell you right now, politically, you never burn your bridges, you never burn your bridges, but she's done it and that has just showed how naive she is as a politician.

PETER MCCUTCHEON: Pauline Hanson also declined an interview request. She faced the media on Tuesday, after Rod Culleton's resignation.

JOURNALIST: Senator Hanson, you've proven yourself to be an effective political campaigner but can you run a large and often complicated, complex political organisation?

PAULINE HANSON: I think I've proven that I can. And I think over the years, to actually come back into this party after 13 years of not being in it, a party that was nearly finished completely, had no runs on the board at all, and in that period of time that I've actually then - and in a year and a half to pick up four Senate seats and the polls now indicating that we're gaining support, a momentum that has - that the other political parties would dearly love to see.

IAN NELSON: We need Pauline Hanson's One Nation, as competition, to put it simply, to the major parties, because they're just so comfortable at the moment so we desperately need them. My only concern, of course, is the anti-Christ of politics - James Ashby, that's my only concern.

LEIGH SALES: Peter McCutcheon reporting.