Wicklow County Council has begun an investigation into another large illegal dump which officials believe was being used until very recently.
The six-acre site near Enniskerry contains up to 100,000 tonnes of construction, demolition and domestic waste which had been dumped at the site over the last five years.
It is believed that the man who owns the land also operates a waste firm which is engaged in recycling.
The operations of the recycling firm are also being investigated by the county council.
Yesterday senior officials from Wicklow County Council described the site as "very significant".
Mr Philip Duffy, acting director of environmental services at the council, told The Irish Times that the site investigation, which began some weeks ago, was still in its very early stages.
"The site has been known to the council for some time, and is one of seven large sites being investigated by the council," Mr Duffy said.
According to a report in yesterday's Sunday Business Post, the owner of the site has said that he is complying fully with county council officials investigating the dump.
Meanwhile, Cement Roadstone Holdings (CRH) has said that it is too early to estimate the ultimate costs of cleaning up an illegal dump at its lands near Blessington in west Wicklow.
The firm was reacting to reports that the total clean-up cost associated with the dump, which contains over 100,000 tonnes of waste, could be €10 million.
Gardaí and officials from Wicklow County Council are currently investigating the illegal dumping at the Roadstone site.
It is believed that last month they sought proposals from the company for cleaning up the site.
"The investigation into illegal dumping is still ongoing and it is too early to speculate about the ultimate cost of the remediation measures," a spokesman for Cement Roadstone Holdings said.
"Roadstone is consulting with the county council and the ultimate decision on remediation will be sanctioned by the EPA," he added.
"Roadstone will take responsibility for the ultimate remediation of the site.
"This dumping was carried out without the knowledge of the company (CRH).
"The company is both shocked and embarrassed that it took place," the CRH spokesman said yesterday.