Poor storage and management of waste at handling facilities is causing an "unacceptable" fire risk, according to the Environmental Protection Agency (EPA).
It received 539 complaints about licensed waste sites last year, according to the agency’s report on waste enforcement for 2014, most of which related to bad odours from the sites.
There were six fires at waste facilities last year and the EPA received almost €40,000 in fines and costs from three waste operators which were brought before the courts after they had breached regulations.
One conviction was secured against Oxigen Environmental from Dundalk after it was found that the company's activities resulted in "significant impairment of the environment beyond the facility boundary", and failed to ensure that vermin, flies and odours did not cause a nuisance in the surrounding area.
The total number of incidents reported to the EPA concerning waste facilities rose from 530 in 2013 to 638 last year, although there was a slight drop in the number of complaints received over the same period.
EPA environmental enforcement programme manager Mary Gurrie said it is targeting companies that continue to break the rules. It was also found that 16 landfills had gas and/or leachate management issues, the latter of which can lead to contamination of surface or ground waters. There were six operational landfills by the end of last year, according to the EPA, which also monitors 61 closed landfill sites.