Charges have been laid over "vile" CFMEU protests as an LNP-sponsored attack ad in Opposition Leader Tim Nicholls' safe Brisbane seat seeks to tie his Labor opponent to the controversy.
The electoral commission is looking into whether the flyer, labelling Labor candidate for Clayfield Philip Anthony "Your Local CFMEU Champion" complies with the Electoral Act, after complaints from Labor supporters.
The ad highlights CFMEU members' threats to rip out the spines and "rape" the children of workers who refused to strike at Glencore's Oaky North mine and has been labelled "defamatory" by the solicitor candidate.
The letterbox drop came as Mr Nicholls continued to ramp up his attack against Labor, having started the Queensland election campaign warning of a personal and dishonest scare campaign from Labor.
"Let's start on a positive campaign, not go down the nasty smear and fear-of-an-idea campaign of the Labor Party," he said, on the second day of the campaign.
The union drew widespread condemnation in October when video emerged of union protesters abusing workers who refused to strike at Glencore's Oaky North mine.
According to News Corp, security reports from Glencore included threats such as "I'll attack you with a crowbar", and "I'll f---ing rape your kids c---".
Queensland Premier Annastacia Palaszczuk labelled the comments unacceptable but refused to cut funding ties with the union.
The Electoral Commission of Queensland confirmed it had received "a very small number" of complaints about the flyer.
"ECQ is now considering whether it complies with provisions in the Electoral Act," a spokeswoman said in a statement.
Two of those complainants, both linked to Mr Anthony but neither members of the Labor Party, told Fairfax Media they were "shocked" and glad their kids had not seen the flyer.
"Particularly when in the same letterbox delivery I get a letter from Tim Nicholls that says, ???like you I'm tired of hearing the same phrases, the same negative scare campaigns' ," said mother-of-two Allison Courtice, who has offered to volunteer for Mr Anthony on election day.
"I'm thinking ???and what's this?' If this is not a negative scare campaign then I don't know what is."
LNP campaign director Lincoln Folo, who authorised the ad, did not return calls to comment.
Earlier this week, Ms Palasczcuk reportedly wrote to Clayfield voters urging them not to vote for Mr Nicholls because of his refusal to rule out working with One Nation if it won the balance of power.
Labor has repeatedly claimed a "deal" between the parties, which Mr Nicholls rejected.
Mr Anthony, a solicitor himself, said he had taken legal advice about the flyer, saying it was a sign Mr Nicholls thought he was in trouble in his own seat.
"It's clearly designed to link me to that language and that is completely and utterly defamatory and it's designed to be that way," he said.
"The fact that he's stooped that low, I mean that distresses my family. Perhaps more them than it does me. As I say, there are kids reading these things."
Mr Anthony, a member of the CFMEU-backed Left faction, said he would not condemn the people involved in the protest but he condemned their actions. The union retained his full support.
On Wednesday, a police spokeswoman confirmed two men had been charged over the protests at the mine.
A 40-year-old Maroochydore man was charged with making threats, details of which were not publicly available, to appear in the Emerald Magistrates Court on December 19.
A 47-year-old man was charged with trespassing, to front the same court on November 28.
