Janice Linden, 35, was convicted of trying to sneak three kilograms (6.6 pounds) of methamphetamine into the country in her luggage through the southern city of Guangzhou in 2008.

“The execution took place around 10.00 am South African time (0800 GMT),” spokesman Clayson Monyela told AFP.

“Our embassy officials were there with her family. She had two sisters who were there,” he added.

“We are disappointed since we would have preferred the death sentence to be commuted to a life sentence instead of the execution.”

Convicted in 2009, Linden had exhausted all possible appeal processes.

South Africa had made several appeals to have Linden’s sentence converted to life imprisonment, including on the sidelines of last week’s United Nations climate talks in her eastern hometown, Durban, that ended Sunday.

“Even on the COP17 sidelines the (foreign) minister summoned the Chinese ambassador,” said Monyela.

“We pleaded for clemency repeatedly.”

Chinese foreign ministry spokesman Liu Weimin told AFP in Beijing that the law had been followed.

“On handling drug criminals, the Chinese government’s position has been consistent and clear,” said Liu. “Whether they are foreign or Chinese, China will handle their cases according to the law.”

Chinese authorities would hand over Linden’s ashes to her family on Monday, said Monyela.

Linden steadfastly insisted on her innocence, an unnamed family member told The Mercury newspaper in Durban.

“She said she didn’t know how the drugs got into her luggage. She thought she was framed.”

The main opposition party Democratic Alliance (DA) accused South Africa of sidestepping human rights issues with its biggest trade partner.

“It is clear that whatever our diplomats have done has not been enough to save Linden’s life,” Stevens Mokgalapa, the party’s deputy spokesman for international relations, told The Times newspaper.

“Drug mules should be punished for what they do. But this is clearly a case of punishment not fitting the crime.”

In October this year, South Africa kept the Dalai Lama from visiting the country for Nobel laureat Desmond Tutu’s 80th birthday.

A government official later acknowledged the decision was influenced by fears that South Africa’s trade relations with Beijing would suffer if the Tibetan spiritual leader were allowed to visit.

According to the rights group Amnesty International, China executes more people every year than the rest of the world combined.

Executions in China have traditionally been carried out by shooting. But increasingly lethal injections are being used.