PRISON officers at the Maryborough jail are being regularly hospitalised as a prison 'fight club' emerges from overcrowding.
There are fears of potentially fatal consequences, if the inmate population is not addressed soon.
There were 664 prisoners inside the prison yesterday putting it more than 30% over the designed capacity of 500.
All 12 of Queensland's high-security jails are overcrowded.
New figures show nearly 280 guards were assaulted in the state last year, compared to 255 in 2016 and 186 in 2015.
Last month, a prisoner faced Maryborough District Court for spitting into an officer's face which was followed by the inmate violently punching them.
Michael Thomas of Together Union, which represents prison workers, said the union had real concerns one of its members could be killed.
"It is a dangerous environment and any assault is one too many," Mr Thomas said.
"Whenever assaults occur, the outcomes can be absolutely very severe."
He said it was a "tinderbox for violence".
"You've got more people rubbing up against each other, two people put in single cells, the kitchen facilities are only designed for a certain number, the benches and tables are set up for a certain number," he said.
"So you've got all these tensions and stresses."
Maryborough MP Bruce Saunders said the government was working to ease overpopulation stress by hiring more staff.
"There's no way to avoid (overcrowding) unless we spend $2-3 billion," Mr Saunders said.
"The public expects people to be sentenced to jail and this is the final results."
Mr Thomas said an increase in staff helped the situation, but was not the final solution.
"To be fair, the government have done a lot of work around increasing staffing.
"That alleviates some of the problem, but not all.
"At a certain point, it doesn't matter how many staff, blocks or cells you have. You need to be doing things that double bunks within cells and trying to increase programs that keep prisoners occupied."