Minister for the Environment, Dick Roche, has said increased greenhouse gas emissions detailed in a new report come as 'no surprise' to him.
The Minister said the increase on 1990 levels had to be viewed in line with the country's economic performance.
He said that while increased emissions in 2005 were disappointing, the rise was well below the level of economic growth recorded in the same year.
According to the new report from the Environmental Protection Agency, greenhouse gas emissions from the transport sector rose by nearly 7% in 2005.
The steep rise is being blamed on an increase in the number of vehicles on the roads as well as a trend towards the purchase of larger sized cars.
Dr Mary Kelly of the EPA has described the rise in emissions as 'particularly worrying' and said major efforts will be required to halt and reverse the trend.
Last year, the EPA identified that sales of cars with engine sizes between 1.7 and 1.9 litres had increased by 400% since 1990.
Its new report has identified that petrol use in 2005 was up 5% and diesel was up almost 9%, leading to an overall transport emissions increase of almost 7%.
Dr Kelly said the rise of transport emissions was by far the largest in any sector and reflected a 160% increase on 1990 figures.
