The amount of waste sent to landfill rose by more than 110,000 tonnes last year, a 40pc increase, unpublished figures from the Environmental Protection Agency (EPA) show.
While overall recycling rates have increased over recent years, the EPA has warned that waste collectors are utilising landfills either due to cost reasons or because they cannot export the waste abroad for treatment.
The figures come as pressure mounts on Environment Minister Denis Naughten to row back on plans to ban flat-fee charges to dispose of black bin waste amid concerns that household bills will rise.
The new system is designed to encourage an increase in recycling rates, and to allow the State to meet binding EU targets to reduce the amount of waste going to landfill.
While the minister has admitted that prices will rise, he insists that any increases will not be "significant".
Under the new system, which comes into force from Saturday next, flat-rate fees will be banned - meaning households which only use the black bin to dispose of waste will pay higher charges. There will be no minimum charge per kilogram of waste disposed, with operators free to set prices.
Waste collectors can offer a range of pricing options to customers. These can include combinations of a standing charge, a fee every time the bin is lifted, a charge per kilogram of waste, or a pricing structure based on the amount of waste produced with an excess charge for amounts above a certain weight limit.
It is expected that the cost to dispose of black bin waste, routinely sent to landfill or for incineration, will be higher than the cost of disposing of compostable waste such as food and garden clippings, and recyclates including paper and drink cans.
However, despite increases in recycling rates over recent years, there is growing concern that households are dumping their rubbish into black bins which is sent to landfill.
In 2013, the amount disposed of in landfill was 381,000. It fell in each of the next two years, but rose sharply in 2016 to 390,000 tonnes, up from 278,000 in 2015.
Separately, figures from the Central Statistics Office show a sharp rise in the amount collected in the landfill levy. This amounts to a €75 charge for every tonne of waste disposed, and figures show that last year, some €37m was collected, up from €28m in 2015, an increase of 32pc.
The EPA has warned that landfill capacity is at "critically low" levels, and that last year extra capacity was authorised to prevent stockpiling of waste or illegal dumping. Seven landfills accepted waste for disposal last year, down from 25 in 2010. The figure has since reduced to six.
"It would be a retrograde step if the quantity of municipal waste disposed to landfill was to start to increase again," it said in its 'Ireland's Environment, An Assessment' report, adding it hoped that the 2015-2016 trend would be "short term".
Separately, figures from local authorities also suggest an increase in the number of complaints about illegal dumping, which rose from 8,900 in 2015 to 10,040 last year.
The easiest way to avoid bin charges, it appears, is to avoid using your bin. A year after the furore which erupted after the Government attempted to introduce pay-by-weight bin charges, it's back on the agenda. But this time, the proposed system is somewhat different.