Hu Yunteng is head of the research department of the SPC.
Beijing - China's top court has overturned, on average, 10 percent of all death sentences nationwide since 2007 when it took back the right of final review from lower courts, a senior court official said.
Hu Yunteng, head of the research department under the Supreme People's Court (SPC), said regaining the review "played an obvious role" in reducing the number of executions.
"It has ensured that the death penalty can only be applied for the most serious crimes," he told China Daily.
But Hu declined to specify the number of death sentences carried out each year.
In 1981, to tackle rising crime, the highest court granted provincial courts the authority to pass death sentences.
The practice, widely criticized following reports of miscarriages of justice, ended on Jan 1, 2007, when the SPC was again given the sole power to review and ratify death sentences.
Hu said death sentences were overturned mostly for lack of evidence, procedural flaws or for an inappropriate penalty.
"The SPC will not tolerate any mistakes regarding evidence or procedure and will thoroughly investigate" questionable judgments, he said, adding that the quality of local courts' handling of death penalty cases is improving.
"We must make sure the use of the death sentence is accurate and free of mistakes to respect and protect the convicts and their rights."
Earlier, Zhang Jun, SPC vice-president, told judicial departments to only impose a death penalty for the most heinous crimes.
The SPC also increased its criminal tribunals from two to five to better examine all death sentences passed, Hu said.
The SPC also ordered that all cases that carried a possible death penalty must be heard at a court session, with the defendant or defendants in attendance, he added.
The move "prevents unjust, false or invalid cases on the one hand and, on the other hand, respects the rights of defendants", he said.
About 90 percent of death sentences passed are for serious crimes ranging from intentional homicide, robbery, serious injury, rape, drug trafficking to kidnapping, according to Hu.
In August, the National People's Congress, the top legislature, dropped the death penalty for 13 economy related, non-violent crimes in the latest amendment to the country's Criminal Law.
Hu said the SPC "strongly supports" the move as it has sent "a positive signal for strictly controlling the imposition of a death penalty".
Despite these moves, he said, the final review still faces challenges, including the use of torture as well as poor standards among some rural judges.
In one of the country's most notorious forced-confession cases, Zhao Zuohai, after serving 11 years in prison, was released in early May after the man he was alleged to have murdered turned up alive.
The Henan farmer said the police tortured him into making a confession.
Zhao Bingzhi, head of the criminal law research committee under the China Law Society, said it's essential for the SPC to classify and summarize cases where the death penalty has been overturned and then release them to guide lower courts.
"What's more, the SPC should go beyond only examining evidence, and establish rules to better define serious crimes where the death penalty is applicable to ensure its appropriate use," he said.