Cassie Sainsbury faces decades in jail as judge throws out her plea bargain.

Australian drug mule Cassie Sainsbury will stand trial for trying to smuggling nearly 6kg of cocaine out of Colombia after a judge rejected a plea deal.

Judge Sergio Leon rejected the deal the 22-year-old Adelaide woman struck with Colombian prosecutors in July, in which her jail term would be reduced from 20 years to six in return for naming people behind a drug smuggling ring.

His decision comes after Sainsbury, who now faces between 20 and 30 years in jail if found guilty, claimed she’d only agreed to smuggle 5.8kg of cocaine in her luggage after her family was threatened.

“In the name of the Republic, and by the law, decides not to approve the agreement held between the prosecutors and the accused, Cassandra Sainsbury, with the help of the person who takes her defence according to what was exposed before,” Judge Leon told a court in Bogota on Thursday (AEST).

Sainsbury made the claim about threats to her family when she appeared before the judge in July.

Judge Leon suspended the hearing in response, saying Sainsbury’s explanation for her actions raised questions about whether the plea deal should be allowed.

As she arrived at court in Bogota on Thursday (AEST), her lawyer Orlando Herran told reporters that Sainsbury was maintaining her story that her family was under threat.

“As the defence, we don’t have the resources of the prosecution,” Mr Herran told Fairfax outside the court.

“At the moment, we only have Cassandra’s words about the threat.

“Cassandra doesn’t have the personal resources for a private investigator to prove the threat.”

Sainsbury was supported in court by mother Lisa Evans and fiance Scott Broadbridge, as well as Australian consular officials.

She told the court she initially thought she was carrying documents for someone in exchange for $10,000, but was later forced to carry drugs after being threatened at gunpoint, News Corp reported.

Foreign Minister Julie Bishop said consular staff were at the court providing Sainsbury with assistance.

“It is a strong message to all Australians travelling overseas,” she told the Seven Network.

“You have to abide by the laws of the country you are visiting.”

LISTEN: Is Cassie Sainsbury the new Schapellle Corby?