The Green Party have called for motor tax to be scrapped and replaced with a new environmental levy on petrol and diesel.
Minister for Finance Brian Cowen announced in his last budget that he was beginning a public consultation on overhauling the Vehicle Registration Tax (VRT) system to reduce carbon dioxide emissions.
Any changes to the system are expected to come into force on January 1st next year.
In a new submission, the Greens today proposed an environmental charge structured on emissions levels, fuel efficiency, and the size and weight of vehicles. The levy is designed to encourage lighter and more fuel-efficient cars.
Electrical cars and dual-fuel vehicles would pay minimal charges or none at all.
The 2007 Budget already allows for VRT relief of 50 per cent for electric cars.
Under the Greens' proposals, large-engine cars with high emission levels will pay up to €6,000 per annum. The new fuel levy proposal can be phased in over five years at a rate of 4 cent per litre or over 10 years at a rate of 2 cent per annum.
The Greens favour the 10-year option to minimise the potential inflationary pressure exerted by the levy.
Party leader Trevor Sargent unveiled the proposals with his transport, finance and environment spokesmen in Dublin.
Last year a report by Sustainable Energy Ireland found the average emission rate for Irish cars at 165g of carbon dioxide per kilometre is above the voluntary EU target of 160g.
Last year, Irish motorists bought 10,519 new cars with engine capacity of 2.4 litres or more, compared to just 1,895 in 1996.
Between 1996 and 2006, the number of cars jumped by 160 per cent, from 109,333 in 1996 to 173,273 in 2006.
Greenhouse gas emissions from transport in Ireland jumped 140 per cent in 14 years, the second highest among EU-15 where the average increase was 25 per cent.