In a statement issued late on Wednesday, the Attorney-General's Chambers (AGC) said parliament formally approved amendments enabling judges to commute death sentences to life imprisonment under certain conditions.
Human rights groups have called for the total abolition of capital punishment in Singapore - carried out by hanging since British colonial rule - but the government says death sentences for the most serious cases will remain as a deterrent.
Before the reforms, judges had no choice but to impose the death penalty on anyone convicted of murder or trafficking in drugs above specific volumes.
Under the amended legislation, a judge now has the discretion to impose life imprisonment on a person convicted of murder if that individual has been found "not to have intended to cause death", the AGC said.
For drugs offences, courts can impose a life term if the accused is found to be "only a drug courier" or "suffering from such an abnormality of mind that it substantially impaired his mental responsibility for committing the offence".
The AGC, which oversees all criminal prosecutions, said it will meet with the lawyers of 34 people facing execution for murder and drugs offences after parliament approved the amendments.
The AGC said the inmates "can apply to be re-sentenced" and the agency will meet with their lawyers to discuss how the new law will affect their cases.
In drugs cases, the public prosecutor must certify that a convicted offender has "substantively" helped the anti-narcotics police disrupt drug trafficking activities within Singapore or overseas, the AGC said.
Defence lawyers will also be invited to find out if their clients would like to help the Central Narcotics Bureau fight trafficking or undergo psychiatric tests to determine whether their death sentences could be reduced.
On Wednesday, Deputy Prime Minister, Teo Chee Hean, rejected calls to abolish the death penalty - also applicable to kidnapping and firearms offences - saying it was still necessary to deter serious crimes.
Mr Teo, who is also minister for home affairs, said abolishing capital punishment would send the wrong signal to potential criminals.
Human rights advocate and executive director of Singapore's Think Centre, Sinapan Samydorai, says one Singapore university professor has spoken of his students being more receptive to "testing" drugs, especially 'ice' or methamphetamine.
Mr Samydorai told Radio Australia's Asia Pacific that young people are rethinking their views on drugs, when in the past there was "never a public debate."
"People automatically thought that there was no choice, I mean the death penalty is there, you know," Mr Samydorai said.
"So I think it [abolition] will make a great impact in terms of mindset.
Mr Samydorai says there are currently 34 prisoners on death row in Singapore - 28 for drug trafficking and six for murder.