Taoiseach Bertie Ahern and Minister for Justice Michael McDowell have questioned the sentences imposed by judges for serious criminal offences following the shooting dead on Sunday of Donna Cleary at a party in Coolock, Dublin.
Mr McDowell said the shooting marked "a watershed point for all our social thinking on these matters".
"I believe that everybody in Ireland, be they elected politicians, ordinary citizens, members of the judiciary, members of law enforcement agencies, anybody who reflects on what happened last night must realise this is a watershed point."
He said serious drugs offences should be "dealt with very, very severely".
Mr Ahern said he was shocked by the killing of Ms Cleary by men who opened fire on a house at Adare Green when refused entry to a 40th birthday party. He said it marked "a new low" and made him wonder if sentences for serious crimes were "just too lenient".
Mr Ahern's and Mr McDowell's comments came as it emerged that one of the three men who gardaí believe is responsible for Sunday's gun attack would still be in prison if the courts had imposed a mandatory 10-year jail sentence when he was caught with a large quantity of drugs in 1999.
The suspect was instead jailed for six years after being caught with drugs worth £150,000. That quantity was 15 times the £10,000 value which would have made him eligible for the mandatory 10-year jail term.
This man, who is from the Finglas area, was one of five people being questioned last night by detectives investigating Ms Cleary's killing. The five include the three men believed to have been involved in the fatal gun attack and a husband and wife who are known to the three suspects. They were all arrested at a house in Co Kildare just before midnight on Sunday.
Apart from the Finglas drug dealer, the other two people believed to have been at the scene of the shooting at Adare Green, Coolock, have addresses in Finglas and Clonee, Co Meath. Both are in their mid to late 20s and are well known to gardaí.
Gardaí believe these two men have been involved in a series of armed robberies including a number of attacks on cash in transit vans in which very large sums of money have been stolen.
Mr McDowell said it "did not wash" with him when drug dealers appeared before the courts claiming they were a "small cog in a big machine".
He said possession of firearms was a "very serious" offence and "must be dealt with in a way which makes an example of any offender".
Speaking yesterday afternoon about the attacks, Mr Ahern said: "Someone coming back indiscriminately, blasting five rounds into the front room of a small house and to kill a 22-year-old mother, it's hard to think of anything that could be much lower than that.
"When you see the amount of crimes and gun crimes, it just makes you feel that perhaps we're just too lenient," he said.
The three suspects had tried to gatecrash a party Ms Cleary was attending at about 2am on Sunday. They were refused entry but returned half an hour later and opened fire on the packed house, fatally wounding Ms Cleary.
A spokeswoman for the Department of Justice said that the Minister for Justice planned to introduce a series of amendments to the Criminal Justice Bill when the Dáil resumes after Easter. It was hoped the legislation would be passed by the time the Dáil rises in July.
The amendments will provide for mandatory sentencing for the possession of unlicensed firearms, stiffer sentencing for modifying firearms and making it a criminal offence to be a member of a criminal gang. A gun amnesty is also being planned.