Jiang Xingchang, vice-president of the Supreme People's Court (SPC), told China Daily that lethal injection would eventually replace shooting in all executions ordered by intermediate courts.
"It is considered more humane and will eventually be used in all intermediate people's courts," Jiang said.
He said half of the country's 404 intermediate people's courts, which carry out most executions, currently use lethal injections.
Human rights organisations estimate China executes more people each year than the rest of the world combined.
Jiang told China Daily that the SPC would assist local courts by distributing the toxin used in lethal injections, rather than requiring court officials to come to Beijing to collect it.
"The SPC will help equip intermediate courts with all required facilities and train more professionals, particularly in the central and western regions," he said.
AI said rather than changing the method of injection, China should be abolishing undignified and inhumane state killings, particularly in the leadup to this year's Olympic Games.
Catherine Baber, Director of AI's Asia-Pacific programme, said: "This move goes against the spirit of the Olympic Charter for the Beijing Olympics, which places the preservation of human dignity at the heart of the Olympic movement.
"There is nothing dignified or humane in the state killing of individuals by whatever means."
The organisation also noted the announcement came only weeks after the UN General Assembly adopted a resolution calling for a worldwide moratorium on executions.
In its statement, AI challenged Jiang to explain how lethal injection was more humane as a method of execution than shooting.
"The extension of the lethal injection programme flies in the face of the clear international trend away from using the death penalty and ignores the problems inherent in this punishment," Baber said.
"Arbitrary application, miscarriages of justice including execution of the innocent, and the cruel and inhumane nature of the death penalty cannot be solved by changing the method of execution."
AI said the "particular concerns" involved with lethal injection included:
- diverting attention from the suffering inherent in the death penalty by suggesting that death by lethal injection is humane. Evidence showed that it can cause convulsions and a prolonged and painful death.
- the potential to cause physical and mental suffering through botched implementation.
- the involvement of health personnel in executions. Virtually all codes of professional ethics that considered the death penalty opposed participation by medical or nursing personnel.
The organisation said it had welcomed the SPC's review of all death sentences passed in China, which came into effect in January 2007, saying the change was expected to result in a reduction in the number of executions.
But it condemned "the lack of transparency" in China which would make it "impossible to assess or verify any change in the number of executions being carried out".
Baber said: "The Chinese authorities must take concrete steps towards the abolition of death penalty.
"As a first step, China must make public the actual numbers of people executed and radically cut the number of capital offences.
"A positive legacy for the Beijing Olympics can only be achieved when China's world record of executions comes to an end."
Consider "ground realities"
In an interview with China Daily, Chief Justice Xiao Yang acknowledged the global trend towards limiting and abolishing the death penalty, and said "China is also working toward that direction".
But he stressed the goal could not be achieved overnight.
"We cannot talk about abolishing or controlling the use of death sentences in the abstract without considering ground realities and social security conditions," he said.
With the strong public belief in the "an eye for an eye and a life for a life", he said it was also unrealistic for China to abolish the death penalty in the short-term, even for non-violent criminals.
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