Seven people have died in traffic incidents across the country since the May bank holiday weekend began last Friday.
The chief executive of the Road Safety Authority, Noel Brett, said he was disappointed at the "tragic" number of deaths.
A man and a woman, both aged 20, were killed when the BMW the man was driving crashed into a pedestrian barrier at Long Walk, Dundalk, at 3am this morning. There were no other vehicles involved. Both were pronounced dead at the scene and have not yet been named.
In Co Kerry, a male pedestrian died when he was struck by a vehicle at Rathduane on the Rathmore to Millstreet road at 9.45 pm yesterday. He was named by gardaí today as Martin O'Connor (22) from Dromscarra, Kiskeam, Co Cork.
Also yesterday, a man died following a crash at Fedamore Cross, Co Limerick, at 10.25pm when a van went out of control and struck a stone wall. The front seat passenger (21) was pronounced dead on arrival at the Mid-West Regional Hospital.
The driver is being treated for injuries which are not believed to be life threatening. Gardaí at Roxboro Road are investigating.
On Saturday, a man died when his motorcycle hit a concrete bollard an Dunkettle, Glanmire, Co Cork. He has been named as Liam Hogan (38) from Ardsallagh in Youghal.
A woman in her 70s died shortly before 5pm on Friday when her car hit at wall at Ballinagh Road, Cavan.
In the North, a man died in a two-vehicle collision in Kesh near Enniskillen, Co Fermanagh, yesterday afternoon.
Mr Brett said he was disappointed at the weekend death toll but said he was encouraged by the fact it was less than the nine who died on the last bank holiday in April.
"It's better than it might have been, but it's still not good enough," he told ireland.com. "Even one crash is too many, never mind one injury or fatality." However, he insisted he was pleased with the public's response to the road safety message as a whole.
Fine Gael's road safety spokesman, Shane McEntee, said the predictions of a low number road deaths over the weekend have sadly "proved premature" with the deaths of five people in the past 24 hours.
Mr McEntee said the carnage was continuing unabated, and it was "disgraceful" that the Government still has not introduced random breath testing and a nationwide speed camera network, more than nine years after they were first promised.
"The fact that 86 people were arrested for drink driving on Saturday night, while a welcome sign of increased Garda vigilance, is also a tragic indication that the safe driving message is not getting through," the Meath East TD said.
According to the Garda Press Office, 320 people were arrested on suspicion of driving whilst under the influence of alcohol and/or drugs over the weekend.
A total of 140 people have been killed on the Republic's roads so far this year.
