David Coburn, who topped Ukip's Brussels list for Scotland in controversial circumstances, stands accused of falsely claiming that leader Nigel Farage asked him to stand. The written complaint also alleges that Coburn had described himself as the party's "Scottish spokesman" when he was not.
Ukip, a party opposed to the EU and mass immigration, has enjoyed success south of the Border and is tipped to be the big winner in May's election for the European Parliament.
The party was also hoping to win an MEP's seat in Scotland but the vicious infighting is undermining its efforts.
Until recently, the Scottish party was led by Lord Monckton and chaired by Mike Scott-Hayward. However, both they and other figures believed a Ukip faction - including former candidate Otto Inglis - was planning a coup.
The divisions flared up during Ukip's internal contest to select candidates for the European election.
Six of the shortlisted candidates, including Monckton and Scott-Hayward, quit the race in protest at the tactics allegedly used by Inglis.
However, the party pushed ahead with the ballot and Coburn, Ukip's London chair, topped the poll.
Ten Ukip Scotland figures - including Scott-Hayward, one-time fundraiser Malcolm Macaskill and another senior figure, Paul Henke - have now signed an official complaint against Coburn. The letter includes several allegations.
The complaint alleges Coburn "falsely stated" that "Nigel Farage had asked him to put his name forward for MEP selection in Scotland".
They also allege that Coburn falsely denied making the claim about Farage.
During the recent industrial dispute between Ineos and trade union Unite, the complainants allege Coburn put out a statement in which he "falsely stated" that he was Ukip's "Scottish spokesman".
The Glasgow-born candidate has also been accused of falsely saying on television that the six candidates resigned because they did not like the result of the ballot. The 10 members claim these alleged statements amount to breaches of the Ukip constitution and rules.
Following the disputed internal poll, Farage sacked Monckton by email and Scott-Hayward resigned as chair. Misty Thackeray, who is on the right of the party, is now interim chair.
Hencke told the Sunday Herald: "I expect the complaint to be investigated properly. I believe Ukip to be an up-front party run by honourable people. We should have honourable people as candidates."
The trouble comes after Farage suffered arguably his worst week as party leader. Ukip was forced to suspend an Oxfordshire councillor after he blamed flooding on the decision to legalise gay marriage, while Farage was also criticised for backing an end to the ban on handguns, and saying that women who had children were worth less to City firms.
"We need a proper gun-licensing system which, to a large extent, we already have and I think the ban on handguns is ludicrous," he said.
He also opened fire at his party's own manifesto from 2010, saying: "It was drivel, 486 pages of drivel. I didn't read it ... it was a nonsense, and we've put that behind us and moved on to a professional footing."
SNP MEP Alyn Smith said: "Ukip are a total farce and barely exist as a party in Scotland - a fact confirmed by their abysmal showing at the Cowdenbeath by-election where, yet again, in a Scottish election they failed even to hold on to their deposit."
A UKIP spokesman said: "We have not received said complaint but when we do we will process it according to the party's rules."