Irish police say unidentified gunmen have opened fire on boxing fans at a Dublin hotel, killing one man and wounding two others.

Detectives have yet to disclose a motive for Friday's shooting in the lobby of the Regency Hotel in northern Dublin, where fans were attending a weigh-in event for boxers ahead of a weekend boxing competition.

Police said all three victims were in their 20s or 30s. One was pronounced dead at the scene. The two others were taken to separate Dublin hospitals with suspected gunshot wounds.