Pauline Hanson has defended One Nation's vetting process for candidates, in the wake of another political hopeful from the party resigning.

Mark Ellis joins Andy Semple, Shan Ju Lin and Peter Rogers on a list of former Queensland candidates who were involved in controversy before their departures.

On Wednesday, Guardian Australia published details of alleged threats Mr Ellis made to a former employee on social media.

Mr Ellis was also thrust into the spotlight last week, when it was revealed he was among a group of police officers charged — and later cleared — of kidnapping Aboriginal boys in 1994.

Senator Hanson, who was unveiling a new set of candidates in Cairns on Wednesday, said her party had a "very tough selection process".

"Sometimes you don't get it right," she said.

"I'm not [in] the selection process but I am on the executive as state president of the party in Queensland.

"It does come down to my final decision. My final decision now is that he's no longer a candidate under the banner of One Nation. He has offered his resignation."

Pauline Hanson says she is not involved in the early stages of picking candidates. ( ABC News: Matt Roberts )

Senator Hanson said Mr Ellis' history in the police was not an issue, but she was not pleased with comments that he had made.

Mr Ellis, who had been running for the seat of Macalister, made a lengthy post on Facebook explaining his decision to quit, but then deleted it from his profile along with campaign material.

"The constant abuse, harassment and threats to myself, my wife, my parents, and my friends — coupled with the damage to my business and my reputation are simply not worth it. I really don't need the job that badly, " he wrote.

"Family has to come first. I am a big target for the leftie media and the pathetic haters due to my success and profile and even though I'm personally OK — it's starting to hurt people close to me."

In the post, Mr Ellis admitted to using harsh words when speaking with the former employee but insisted he was not a thug or a bully.

"I guarantee my staff will back me up on that," he wrote.

Ex-One Nation candidates plan fightback

Meanwhile, a group of dumped One Nation candidates have said they are planning to launch their own political party.

Former candidate for the far north Queensland seat of Mulgrave, Peter Rogers, said the ex-candidates had formed an online chat group called EX-PHON, or Ex Pauline Hanson One Nation.

Mr Rogers, who was disendorsed by the party earlier this year, said the new party would launch in May and would include several high-profile members, but he would not elaborate further.

"We have quite a lot of different people, that are of the same values, and I mention that word values as something that I believe that other political parties do not have," he said.