Gardaí believe the victim, Ger McMahon, may have known his killer. He died several hundred yards from his own home.
It is believed the victim and the likely killer may have had a relationship with the same woman.
Mr McMahon, 43, from Raheen Square, Ballinacurra Weston, was found with multiple stab wounds lying outside a house at Lenihan Avenue, Prospect, at about 12.30am. Mr McMahon, who was known to gardaí, suffered stab wounds to the back and upper body.
Ambulance control at the Mid-Western Regional Hospital alerted gardaí at 12.40am. However, shortly after being rushed to hospital, he was pronounced dead.
The investigation is being led by Supt John Scanlon and Det Inspector Tom O’Connor of Roxboro Road Garda Station.
Gardaí were last night trying to trace the movements of known associates of the dead man and were searching for a murder weapon.
An initial examination of the scene indicated Mr McMahon tried to run from his assailant before collapsing on the steps of a house where a couple and their young children live.
Det Insp O’Connor said: “We would appeal to anybody who may have been in Ballinacurra Weston or Prospect areas after midnight to contact us.”
Detectives from the Garda Technical Bureau joined the investigation yesterday and Dr Marie Cassidy conducted a postmortem.
Mr McMahon, who was single, had a number of court convictions, many of which were for burglaries.
He had no links to the city’s feuding gangs.