Headline crime was down ten per cent in the second quarter of 2004 compared to the same period last year, according to figures released by the Department of Justice.
Headline crimes are defined as "serious, indictable offences".
The figures, which are compiled by the Garda Commissioner, show a four per cent drop over the 12 months up to the end of June this year compared to the same period in 2003.
The total number of reported headline crimes in the past year was 99,526, compared to 104,028 in the previous 12 months.
The murder rate has dropped by 19 per cent in the last year. There were 52 murders in 2001 and 46 in 2003. There have been 17 murders in the first six months of this year, which is an annual rate of 34.
The number of assaults causing harm is also down 19 per cent while arrests for drugs possession or sale are down 17 per cent.
However, the figures show an increase in the number of gun crimes in the past six months. Crimes involving the firing of weapons are up by 63 per cent and armed robberies of cash or goods from trucks and security vans are up by 15 per cent.
Rapes of women in the first six months of this year are up by 52 over the 190 reported in the first half of 2003, representing a 27 per cent rise. Section 4 rapes, which include oral and anal assaults, are up 22 per cent to 39 this year, while aggravated sexual assaults are up by 175 per cent from four in 2003 to 11 so far in 2004.
The Minister for Justice, Equality and Law Reform, Mr McDowell, said that while he was "cautious about extrapolating trends over short periods", he welcomed the statistics showing crime rates were dropping.
He said he was determined that the "new tougher approach" which he has taken to the length of life sentences will be adhered to, "so that would-be murderers should fully understand that the taking of a life will result in very severe punishment."
He said he had "grave reservations about drawing any encouragement" from the drop in drug-related arrests due to the lack of evidence that there has been a corresponding reduction in drug use and supply.
Mr McDowell said the lower number of street assaults is attributable to the improving public order situation and a curbing of alcohol abuse to the Public Order Act.
He said he intends to strengthen the law on firearms in the recently-published Criminal Justice Bill to tackle the spread of gun crimes. He said he was studying proposals for mandatory minimum sentences for serious firearms offences, on a par with the current system for drugs crimes.
"I believe that such a change is necessary to confront the gun culture and to preserve our status as an unarmed state with unarmed policing," the minister said.
