Peter Taylor was reportedly one of two men who was seriously injured after the attack at Bray Boxing Club in Co Wicklow, south of Dublin, at about 6.55am on Tuesday.
A second injured man, aged 35, was wounded severely in the leg.
"We know that the gunman left the scene in a silver Volkswagen Caddy".
A 30-year old man has been killed and two other men seriously injured after a shooting at a boxing club in Ireland linked to Olympic champion Katie Taylor. It was set up by Pete Taylor in 1996.
Anyone who wishes to contact Gardaí on this matter can do so by calling Bray Garda Station on 01 6665300, the Garda Confidential Telephone Line 1800 666 111 or any Garda Station.
The gym is owned by Bray municipal council and operated by Mr Taylor.
Lightweight Katie Taylor won gold at the London Olympics in 2012 and is a world boxing champion.
The club is located at the harbour in Bray town.
Gardai said the body of the man remains at the scene pending the arrival of the State Pathologist.
"A number of people had gathered to commence a gym session", said Garda Superintendent Pat Ward at scene of the shooting.
Local Sinn Fein MP John Brady said the incident had brought "another dark day for Bray".
Ireland's Health Minister Simon Harris called the news from Bray "shocking".
The garda helicopter has been circulating the scene while the armed response unit is also in the area as gardai go door to door with their enquiries.