New figures from the Revenue Commissioners show that over €49 million worth of drugs was seized by Revenue's Customs services last year.
In total €49.3m worth of drugs was seized in 2012 compared to €24m in 2011.
Figures show that €33m worth of cocaine and heroin was seized by customs in 2012 compared to almost €10m in 2011.
The Revenue figures also show that Customs seized more than €50m of illegal tobacco and cigarettes and almost 877,000 litres of illegal fuel last year.
Overall the figures show that there were 50 convictions for serious tax and custom offences in 2012 compared to 30 in 2011.
Another 159 cases involving serious evasion are continuing while a further 37 are before the courts.
There were also 2,434 convictions in 2012 resulting in €7.67m in fines and penalties - the majority of which were for the non-filing of tax returns.
The other convictions related to oil laundering and motor tax offences. The figure for 2011 was 2,618.
Sheriffs made around 435 enforced collections a week in 2012, with another 175 weekly enforcements by solicitors and by legal attachment.
The number of enforced collections overall, however, was down 30% on the previous year.