But on Sunday, the government approved an 18-month extension following "explosive evidence" and due to the volume of material and additional time needed to cross-examine relevant witnesses.
"The extension will ensure the commission has sufficient time to fully investigate the serious allegations that have emerged," a statement read.
The revised deadline of December 3 next year will allow for additional public hearings, the presentation of further case studies, and the cross-examination of key persons alleged to have engaged in wrongdoing.
The inquiry has so far heard damaging evidence from public servants, union officials and industry figures into how the former Queensland Labor government dealt with unions, contractors and workplace laws on major infrastructure projects.
Premier David Crisafulli said more than 1350 notices had been issued, more than 560,000 documents obtained and more than 100 witnesses interviewed.
"Queenslanders have been shocked by the allegations of violence, bullying, intimidation and misogyny on and off worksites by the CFMEU," he said in a statement.
Deputy Premier and Planning Minister Jarrod Bleijie said Queenslanders deserved to know the full extent of the CFMEU's conduct and its alleged links with, and influence on, the former Labor government.
"This commission of inquiry has already uncovered shocking allegations of bullying, misogyny, intimidation and violence on Queensland worksites, and it is critical this work continues," he said.
"That is why the Crisafulli government has agreed to extend the commission, to ensure every allegation can be thoroughly investigated and no stone is left unturned."
The commission, led by Stuart Wood KC, is probing the influence of the CFMEU and the now‑scrapped Best Practice Industry Conditions (BPIC) policy on major Queensland projects.
