Road safety chiefs have expressed horror at a 106pc hike in the number of motorists arrested for suspected drug driving so far this year.
Hundreds have tested positive for drug and drink-driving during the Covid-19 pandemic lockdown.
The figure has soared despite a 70pc reduction in road traffic volumes because of the restrictions in place since March.
Road Safety Authority (RSA) figures indicated that cocaine and cannabis are the drugs now most commonly detected in drivers killed in crashes.
The RSA also revealed there was a 17pc increase in driving under the influence according to specimens analysed between January and June.
However, RSA, gardai and road safety campaigners are shocked by the hike in drug-driving, with 1,216 arrests so far this year.
The figure compares with 591 arrests in the first six months of last year - a staggering 106pc increase.
A key element is the new testing equipment issued to gardai and a broader testing regime.
One in three drivers killed in road traffic collisions also tested positive for alcohol in their system.
Junior Transport Minister Hildegarde Naughton said the figures were a cause for concern.
"The data on drink driving highlights the fact that despite improvements in road safety we continue to see a cohort of drivers engage in risky behaviour," she said.
"The evidence of drink and drug driving during the Covid-19 lockdown period demonstrates the blatant disregard that some drivers have for the law and road safety."
RSA chairperson Liz O'Donnell admitted that Ireland now has a major problem with drug driving.
The warning came as motorists were urged to drive with care over the August bank holiday weekend as gardai warned that they will be operating nationwide safety and speed checks.
The warning came as road safety officials expressed concern at the spiralling number of lives being lost on Irish roads.
A total of 83 people have died on Irish roads this year, a near 7pc increase over the same period in 2019.
Officials warned that, when the lockdown and its impact on traffic volumes is taken into account, Ireland is facing an effective 25pc plus hike in fatalities.
One road safety campaigner, Christina Donnelly, pleaded with drivers not to drink or take drugs and drive, to slow down and to exercise maximum care on Irish roads.
Traffic volumes on Irish roads are expected to soar over the next fortnight as most Irish families holiday at home.
"Every bereaved family is a member of a club that none of us ever wanted to join," Ms Donnelly said.
"We have been sentenced to life membership of this club through having lost a loved one on Irish roads. I'm issuing this appeal because I don't want any other family to suffer the heartache of being in this club."