Gardaí arrested 16 people suspected of drink or drug-driving on Christmas Day.

The numbers are up on last year when 11 people were detained on suspicion of intoxicated driving.

There have been more than 650 detections since the launch of the Christmas Road Safety Campaign at the end of November.

Assistant Garda Commissioner David Sheahan says the increase in Christmas Day arrests is a big cause for concern.

"Within that 16, four of those were totally drug-related, so that represents 25 per cent of those arrested yesterday," he said.

"We're trying to get the message out to people not to take risks - don't ever drive while you're under the influence of drink or drugs."