Ms Vega died from cardiac arrest and a post-mortem examination found 26 condoms, each containing 20g of cocaine, in her stomach.
She died 37 minutes after one of the packages burst. Police said the cocaine was worth $120,000 to $190,000.
"There are always serious risks to health when smuggling drugs internally and this woman has paid with her life," said Detective Inspector Scott Beard at the time of her death.
Police soon discovered Ms Vega was the mother-in-law of Peter Leaitua, a mixed martial arts fighter, who was on the same flight from Argentina.
The 40-year-old was wanted by Argentine police on drugs charges and a "red notice" was issued by Interpol in November.
A month later, Auckland drug squad detectives said Leaitua had been arrested and charged with importing cocaine.
He was released on bail and a trial date has been set for November.
The Weekend Herald can reveal that police have charged Leaitua with the manslaughter of Ms Vega.
Bill Hodge, associate professor of law at the University of Auckland, said the manslaughter prosecution was "imaginative" and worthwhile in his opinion.
He could not recall a similar case in New Zealand, but compared the prosecution to "felony murder" in countries such as the United States or Canada. When someone is killed accidentally during a serious crime, the person responsible for the felony can be charged.
This included the death of an accomplice, Professor Hodge said.
He believed the Crown had to prove that Leaitua organised the cocaine smuggling and knew Ms Vega had swallowed the drugs to conceal them while crossing the border.
"This is a very interesting case. Obviously nobody intended for the package to burst, but that has to be a possibility when you ingest a dangerous substance."
Senior police were so worried at the number of New Zealanders being caught as drug-trafficking "mules" that a warning was issued last year.
As well as the risk of death or serious illness, Assistant Commissioner Malcolm Burgess said, mules caught in some countries would receive a long jail sentence or even the death penalty.
"The risks these people take are huge," he said.
The former head of the Maori Language Commission, Sharon Armstrong, is serving a five-year sentence in an Argentinian prison after 5kg of cocaine was found in her suitcase.
She had arranged to fly to London to meet a man after months of online exchanges and agreed to fly via Argentina to pick up some "paperwork" for him.
A judge accepted she did not know the drugs were in her suitcase - but that was not enough to clear her. Armstrong is appealing against the conviction.
Cocaine is a highly addictive drug that stimulates the central nervous system. It reduces appetite, increases energy and provides a euphoric sense of wellbeing.
New Zealand has not been a large market for cocaine, as methamphetamine has been the drug of choice, although organised crime syndicates have worked hard to establish a foothold in recent years.
The amount of cocaine seized in 2008 was just 733g. Nearly 9.5kg was seized in the first three months of this year.
Police believe Auckland is often a transit point for the class-A drug to be trafficked from South America to Australia, then possibly to Europe.
Four men were arrested in Auckland in March when 2kg were confiscated.
Police believe they were part of a syndicate responsible for importing cocaine worth $18 million seized in Australia.
