Singapore, which carries out executions by hanging, on Monday unveiled legal reforms that would enable judges to impose life imprisonment on low-level drug couriers and people who commit murder with "no outright intention to kill".
Judges currently have no choice but to impose the death penalty on anyone convicted of murder or trafficking in illegal drugs above specific volumes.
Under the new laws, expected to come into force later this year, inmates on death row would also have the chance to ask for their sentences to be commuted to life imprisonment.
"Amnesty International welcomes the Singaporean Government's move towards putting an end to the mandatory death sentencing for drug trafficking and homicide cases," the human rights group said in a statement.
The proposed changes could save the lives of inmates on death row, it added.
Officials say there are currently 35 inmates on death row in Singapore, although executions have been suspended since July 2011 as part of a review that led to the proposed new legislation.
From 2004 to 2010, a total of 26 Singaporeans and 12 foreigners were executed in Singapore, according to government figures.
A group called the Singapore Anti-Death Penalty Campaign (SADPC) also welcomed the changes in the application of the death penalty as "a positive message that the government recognises the need for legal reform".
However, Amnesty and the SADPC called for the complete abolition of the death penalty and questioned the government's long-held position that capital punishment serves as an effective deterrent to serious crimes.
"There is no evidence to demonstrate that the death penalty deters crime more effectively than other punishments," Amnesty said.