Overcrowding in prisons is leading to intimidation and violence, according to the Prison Officers Association.
There has been an increase in the number of prisoners put on protection for their own safety.
Figures show the number of significant gang figures behind bars in Irish prisons now stands at around 300, up 50 on the last two years.
The association's annual conference in Sligo today will hear how prisoners are forced to sleep on mattresses on floors because of increased numbers in the system.
Jim Mitchell, Deputy General Secretary of the Prison Officers Association, says prison overcrowding is a primary cause of violence.
Mr Mitchell said: "There's a huge degree of violence in prisons, it's exacerbated by the overcrowding issue. We still have significant levels of violence, particularly in places like Mountjoy."
"We've been campaigning and looking for a specific place to go and put violent prisoners within the system. In the last years that the violence reduction unit was opened in the Midlands Prison, while we recognise that this is a step forward, it can only house a maximum of 10 prisoners at any given time.
The Irish Prison Service set up a National Violence Reduction Unit in Midlands Prison last year, which is to cover the whole of the country.
"We've much more than 10 violent prisoners within the system. What we are looking for is that the National Violence Reduction Unit would be placed in each one of the closed institutions."
“While it represents a degree of progress from our perspective it isn't enough. This unit takes some of the most prisoners in the country and takes them in and endeavours to rehabilitate them and reduce the amount of violence these people regularly perpetrate.”
He said the bonus for staff in this unit is that they are adequately safeguarded with proper personal protective equipment, including battle jackets and batons.
Mr Mitchell said they wanted the IPS to pilot body cameras in the national violence unit and then roll them out to all officers.
“For some reason or another the IPS aren't going with that,” he said.
He outlined what prison officers have to put up with every week, saying there is an average of one assault each week on staff by inmates at Mountjoy Prison in Dublin.
He said: "You take a look at the likes of Mountjoy where there is on average one assault per week by prisoners on staff.
"These kind of assaults are where staff are cut, punched or bitten is what you are talking about in Mountjoy Prison. You have various elements of that across the entire State."
He added: “It's the same prisoners, it's by and large the same prisoners have the same propensity for violence and the same ones that are going at our guys regularly.”
The conference is due to be addressed by Justice Minister Charlie Flanagan later. Senior management from the IPS are also due to attend.