The Central Statistics Office figures also show increases in bank robberies, burglaries, arson and drug production, compared with the same period last year.
A sharp rise in kidnappings also occurred, mainly due to a new offence of human trafficking. There were 15 such cases between April and June this year.
On the plus side, 11 of the 14 crime groups recorded a drop, including significant falls in overall homicide offences, assaults, fraud and public order offences.
Justice Minister Dermot Ahern expressed concern at the rise in murders, many of which, he said, were gangland-related. There were 15 murders between April and June, compared with eight in the same period last year.
The scale of gun crime is also reflected in the number of shootings, jumping from 49 to 68 in the last quarter.
Mr Ahern said: “I am concerned at the increase in the number of murders. Many of these were gangland-related, and it was partly to combat this trend that I piloted significant legislation through the Oireachtas in the past number of months, including the Criminal Justice (Amendment) Act and the Criminal Justice (Surveillance) Act.”
Fine Gael justice spokesman Charlie Flanagan said the hike in murders was “the bloody legacy of Fianna Fáil’s failure to tackle gangland crime” and said gangland here now rivalled “Italy’s Cosa Nostra”.
Deputy Garda Commissioner Martin Callinan said the new legislation would “assist gardaí in taking on criminal gangs”.