The number of people sent to prison last year increased by 13 per cent to 12,339.
In its annual report for 2009 the Irish Prison Service said the number of people sent to prison for not paying court ordered fines increased by 90.7 per cent from 2,520 to 4,806.
This follows on from an increase of 88.7 per cent in 2008.
The number of prisoners committed serving sentences of three to five years increased by 35.5 per cent last year to 469. There was an 80 per cent rise in the number serving such a sentence for drug offences - from 77 to 139.
The number serving sentences of 10 years or more has increased by 114 per cent since 2007 to 70, the report notes, while the number serving life sentences increased by 10 per cent to 22.
The daily average number of prisoners in custody last year was 3,881- up 9.5 per cent on 2008. Most prisons operated at or above full capacity.
The average cost of providing a prison space in 2009 was €77,222, a decrease of €15,495 or 16.7 per cent when compared to 2008.
There were 673 committals in respect of immigration issues involving 669 detainees.
Fine Gael spokesman Charlie Flanagan said the report was an "indictment of the failure of Minister Ahern to put in place a prison system that works".
“Despite the best efforts of an over worked prison service staff, the penal system in Ireland is operating in a completely dysfunctional manner. In short the wrong people are being locked up," he said.
Mr Flanagan noted the report found there was a 90 per cent increase in the numbers of people imprisoned for non-payment of fines last year compared to 2008. "At the same time, on the Minister’s own admission, between 1998 and March 2010 only 23 out of 193 gun murders have lead to convictions."
