A new report from the Environmental Protection Agency has identified that nearly 20% of Ireland's urban wastewater is being discharged with little or no primary treatment.
The report does, however, identify a significant increase in secondary treatment across the country over a two-year period.
The EPA defines urban wastewater as material coming from domestic or industrial sources in cities, towns and villages with a population equivalent of over 500.
In its latest report, it found that 82% of this material received secondary treatment at the end of 2005, up from 67% in 2003.
However the EPA also found 18% of wastewater is still being discharged without treatment or with only basic treatment. It said that in 30 locations the material was released into estuaries or coastal waters.
The Minister for the Environment, Dick Roche, said excellent progress was being made but acknowledged further urgent action was required. He said the required funding had been made available by his department.
