The Fingal area of north county Dublin has the highest percentage of primary school children in classes of 30 or more in the State, with almost one in three students finding themselves in this position, according to Government figures.
As almost half a million primary pupils prepare to return to school next week, the figures also reveal that almost 110,000 primary school children had 30 or more students in their class last year. Nearly 175,000 others went to school in classes of 25 to 29 pupils. This is despite Government commitments to bring down class sizes.
At 32 per cent of all pupils, Fingal had the highest percentage of students in classes of 30 or more. But it is closely followed by other areas such as Minister for Education Mary Hanafin's constituency of Dún Laoghaire-Rathdown and the commuter counties of Laois, Louth, Meath and Wicklow. Each of these had at least 30 per cent of students in classes of 30 or more.
The statistics for the 2006 -2007 academic year were released in a written Dáil reply to the Labour Party's spokeswoman on education, Jan O'Sullivan TD, last week.
They show that 8,175 students - or 32 per cent of the total - in the rapidly growing Fingal area were in classes of 30 or more. A further 13,025 were in classes of 25 to 29 students. Overall, 109,376 primary pupils were taught in classes of 30 or more last year.
This represents 24 per cent of the total primary school population of 455,455, and a decrease of just 2,382 when compared to the previous year.
However, the overall primary school population has risen by around 13,500 since last year.
A further 174,425 - or almost four in 10 - pupils were taught in classes of 25 to 29 nationally. Less than 15 per cent of primary school students went to school last year in classes of under 20.
In the 2002 Programme for Government, Fianna Fáil and the Progressive Democrats said they would reach class size targets of fewer than 20 for all children under nine.
However, Ms Hanafin subsequently acknowledged that these targets would not be met.
At Fianna Fáil's pre-election ardfheis last March, Taoiseach Bertie Ahern personally intervened in the class size row by announcing plans to hire 4,000 extra primary teachers.
The current programme for Government says the extra teachers will reduce class sizes by reducing the staffing schedule in schools from a general rule of at least one teacher for every 27 pupils in 2007/08 by one point a year. Eventually, this will lead to one teacher for every 24 children by 2010/11.
The figures show that children in more rural areas such as Longford, Leitrim, Roscommon, Galway county and Sligo are less likely to go to school in classes of 30 or more. For example, 13 per cent of Longford children and 14 per cent of Leitrim children have to attend classes with 30 pupils or more.
The general secretary of the Irish National Teachers Organisation, John Carr, said class sizes in Ireland are still unacceptably high by EU standards.
However, he said the promised measures, if implemented, would bring about a major improvement.
He added that the union will continue to monitor the situation closely to see that Government commitments were honoured.
Ms O'Sullivan said she had been seeking the information since the start of the year, and criticised the length of time it had taken for it to be furnished to her.
"The figures are worst in the rapidly expanding commuter areas and reflect a shocking lack of planning on the part of the Department of Education," she added.