The collision occurred on the Cork Road (R680) in Waterford City shortly before 8pm on Sunday.

The sole occupant of the second vehicle, a woman in her 50s, was also taken to the hospital for assessment.

A female occupant, also aged in her 20s, was taken to Wexford General Hospital for treatment.

The cyclist was conveyed by ambulance to Beaumont Hospital, Dublin, where his condition is understood to be serious.

The man was conveyed to Midlands Regional Hospital, Tullamore, where he remains in a serious condition.

At around 1.20pm, gardaí and emergency services were alerted to a collision involving a car and a jeep on the N4 at Ardcarne.