Over 450 tonnes of hazardous waste went unaccounted for in 2004, according to report published this morning.
The National Waste Report 2004 said that 453 tonnes of hazardous waste has gone unaccounted for but believes this is "likely" due to incorrect reporting.
"It is likely that an increased emphasis on enforcement will be a feature of data compilation for national waste reports," the Environmental Protection Agency (EPA) said.
The EPA called for greater monitoring of waste management services after the report also found that 23 per cent of households do not have their waste collected.
It wants local authorities to carry out audits of waste management and disposal firms and to ensure accurate reporting. It also wants investigations into what happened to the 227,000 tonnes of household waste not collected.
But Minister for the Environment Dick Roche expressed satisfaction over the report's finding that recycling rates are on the rise and set to meet national and EU targets.
A third of municipal waste and almost 20 per cent of household rubbish was reclaimed in 2004, the report found. The amount of rubbish ending up as landfill fell slightly in both municipal and household categories.
The national target on recovering packaging waste - set at 50 per cent by 2005 - was exceeded in 2004, with 56.4 per cent of the rubbish saved. But there is still a long way to go before to meet the household recycling target of 50 per cent recycled by 2013, the report found.
Municipal waste is already only 2 per cent off the 2013 aim of 35 per cent recycled.
The EPA figures revealed there was a rise in bring banks and civic amenity recycling sites in 2004, and a drop in the number of landfill sites accepting municipal waste.
Dr Gerry Byrne, EPA programme manager said: "The remarkable growth rates in waste recycling year-on-year show that national policy, legislative measures and awareness campaigns are working."
Additional reporting