COVERT recordings of senior council officials criticising a female trade union official were made after concerns were raised about the safety of other women members.
The stinging comments are understood to have been made by senior officials at Causeway Coast and Glens Borough Council.
Audio clips, which were posted online last week and include personal criticism and profanities, singled out the female trade union representative and a well-known community activist.
A senior Nipsa official has now written to the DUP mayor of the borough, Ivor Wallace, to lodge a formal complaint.
It is understood the union representative had raised concerns with council chiefs over car parking arrangements for female staff members.
It is believed that after losing their free parking facilities the workers were forced to relocate to another carpark, which meant they had to walk a distance often in the dark while carrying electronic equipment, such as laptop computers.
It is understood some council workers felt unsafe walking in the dark while carrying equipment.
One recording includes two senior members of council staff discussing the issue during which a profanity is used to describe the union official.
Further disparaging remarks are made in a separate recording.
In the letter to Mr Wallace, a Nipsa official said the union was aware of "appalling conversations" between three named members of council staff.
The letter said the conversations included the use of "extremely derogatory and profane language" about the official which has had an "extremely negative impact".
It also claims that "derogatory and offensive comments were made about other female Nipsa members employed by the council."
The existence of the recordings, which is being investigated by the PSNI, was revealed by The Irish News last week.
Around the same time the recordings were posted online an email was circulated to elected representatives and staff members, which included a summary and partial transcripts of the exchanges.
Sources say they secret recordings were made over a nine-month period in 2022 after bugs were planted in more than one council official's office.
It is understood that hundreds of hours of recordings were made before the bugs were removed.
Sources say that during council meeting on Monday Mr Wallace said the issue of the recordings could not be discussed.
A spokeswoman for Sinn Féin at Causeway Coast and Glens council declined to comment when contacted “because there are ongoing processes and it would be premature to make any comment at this stage”.
The SDLP declined to comment.
