Over 30 industrial tribunals have been taken against the Northern Ireland Prison Service by its employees since 2015, official figures have revealed.
Cases against the Department of Finance (DoF), which is responsible for personnel employment, ranged from victimisation, to sex, religious and disability discrimination, among others.
Out of the 33 cases, the DoF lost just one and paid out £21,632 after the tribunal found there was failure to make a reasonable judgment.
Industrial tribunals are independent judicial bodies in Northern Ireland that hear and determine claims to do with employment matters.
The figures were released by the department following a Freedom of Information request.
Two tribunals were taken up by Northern Ireland Prison Service (NIPS) staff in 2015, six in 2016 and 2017, 10 in 2018 and nine in 2019.
Ivor Dunne, chair of the NI Prison Officers' Association, said he was "shocked" to see the tribunal case figures. He added that the statistics failed to show how many cases were settled outside of the courtroom.
"Each of these costs so much money between solicitors and everything else that comes with it," added Mr Dunne.
"We would help quite a few of the prison officers who take up the cases and the Prison Officers' Association would be funding most of those.
"Just because one case was lost, that doesn't mean to say that they hadn't paid outside the court. Those figures don't tell you that."
Reflecting on the difficult circumstances prison officers have been working under during the Covid-19 pandemic, Mr Dunne said their professionalism has come to the fore.
"Prison officers are committed to their job and it shows as the prisons are functioning basically as normal within Public Health Agency recommendations," he added.
"To be able to function within those recommendations and constraints, it shows you the professionalism of the prison officers. We are frontline workers and because we don't drive a vehicle with a blue light on it, it's almost as if we're the forgotten workforce."
A spokesperson for the NIPS stated that it employs over 1,500 people - meaning 2% of the workforce took employment tribunal cases and only 0.06% were successful.
It added that as part of the Northern Ireland Civil Service (NICS), the NIPS is committed to providing equality of opportunity to its staff.
"It is NIPS policy that all eligible persons shall have equal opportunity for employment and advancement on the basis of their ability and aptitude for the work," said the NIPS.
In order to provide high quality service, the NIPS said it continues to recruit, develop and promote based on qualifications and ability.
"Equal opportunities is central to this," they continued. "We aim to foster a culture which encourages every member of staff to develop his or her full potential by creating a working environment where diversity is valued and respected.
"As part of the NICS, the Prison Service will continue to promote equality of opportunity and fair participation within the framework of the law and will strive to achieve a workforce that is representative of the society which it serves."