After being found guilty, the New Zealander was given a death sentence with a two-year reprieve, meaning if no further crimes were committed in jail, the person could apply to have the sentence reduced to life imprisonment.
Amnesty International said that the Asian superpower executed thousands of prisoners every year. Trials were held in secret and there was no presumption of innocence.
The Kiwi launched a legal challenge in 2010 but the conviction was upheld in the Chinese court of appeal. The prisoner was still trying to convert the sentence to life imprisonment.
Foreign Minister Murray McCully said he had closely monitored the case. "The Ministry's consular staff are working closely with the family and I am being kept updated."
A spokeswoman for the Ministry of Foreign Affairs and Trade (MFAT) said: "New Zealand Consular staff have continued to provide regular consular assistance and support to the detainee."
She said the prisoner's family had requested privacy.
The revelations of the death sentence have provoked an outcry among human rights campaigners.
Amnesty International New Zealand media and communications manager Anita Harvey said: "We were surprised about the death penalty case. We would always engage on the death penalty."
Former New Zealand ambassador to China Tony Brown said he was unaware of the death penalty case. He added it would be unusual for anyone with a reprieve attached to the conviction to be executed.
"At the end of the reprieve period and, if there have been no further problems, the sentence is normally commuted to a prison sentence."
The citizen is one of more than 800 New Zealanders in overseas prisons.
Figures released to the Herald on Sunday show 86 Kiwis in 27 countries, as far-flung as Serbia and Montenegro and Panama, have sought consular assistance from MFAT and remain in prison.
These include well-known cases such as Sharon Armstrong - who was sentenced to a four-year, 10-month jail term for cocaine-smuggling in Argentina - and Danielle Te Kani and George James, who were sentenced to seven and nine years respectively, for drugs charges in Japan.
There are also 771 New Zealand-born people imprisoned in Australia, up from 565 in 2003. Figures obtained from Australian Bureau of Statistics show that 68 of those are in prison for homicide related crimes.
Justice Minister Judith Collins said there were no plans to allow New Zealanders to serve their sentences at home.
"New Zealand does not currently have formal prisoner transfer agreements in place or plans to progress work in this area.
"Just as we expect foreign visitors to our country to abide by our laws, we expect New Zealanders abroad to abide by the laws of the country they are in."
Hard line
* Offenders sentenced to death in China are offered either bullet or injection.
* There are thought to be more executions in China than in any other country, although the exact number is a secret.
* There is no presumption of innocence in Chinese law and confessions are sometimes taken before the suspect has had access to a lawyer.
* Convicted prisoners are killed by a single shot to the back of the head or by lethal injection inside a mobile execution truck.
