CCTV footage apparently showing bin collectors mixing food waste with recycled materials is being investigated, a council has confirmed.
The footage was captured in the Newtownbutler area of County Fermanagh.
It showed brown kitchen caddies of food waste left out by householders being opened and emptied into blue bins containing recyclable items.
The contaminated blue bins were then emptied into the collection lorry, contaminating everything in the lorry.
It is understood this happened on at least three occasions, and a number of residents submitted complaints.
County Fermanagh-based newspaper The Impartial Reporter said the council was investigating the issue last month.
After the issue was briefly raised at a council meeting last week, Fermanagh and Omagh District Council said an investigation was under way.
Ulster Unionist councillor Mark Ovens raised "what seems to be very significant disruption to certain bins on a number of routes".
He said he feared that due to delays in brown bins being collected, some householders were running out of space and mixing waste.
Mr Ovens then discussed the CCTV footage apparently showing council operatives also mixing waste.
"I'm not going into specifics, because I know there is an investigation under way, but in terms of the media reports, I do feel as councillors we weren't particularly well served around the council's response," he said.
"When I read that it would take 'x number of days' to provide a response, the council did not respond until well into the following week, and that could easily have been dealt with in a much better way."
Following the meeting, the council was asked when the investigation into the matter began.
A spokesperson replied: "Immediately on notification of the incident, Fermanagh and Omagh District Council commenced an investigation in line with its policies and procedures.
"The investigation is ongoing at present.
"The council remains committed to delivering a high-quality refuse collection service to residents and encourages and thanks them for their continued support to 'reduce, reuse and recycle'."