'Big' chance Sainsbury innocent: lawyer

The lawyer for accused Australian drug mule Cassandra Sainsbury is hopeful a Colombian court will find her innocent when she stands trial for trying to smuggle nearly six kilograms of cocaine out of the South American country.

A judge on Thursday (AEST) rejected a plea 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.

Judge Sergio Leon's decision came two weeks after Sainsbury claimed she'd only agreed to smuggle 5.8kg of cocaine in her luggage after her family was threatened.

Her lawyer Orlando Herran says there is a good chance she will be found innocent rather than being sent to jail.

"We aim to have a sentence between 21 to 30 years, but the possibility, a big possibility, to obtain an innocent sentence," he told the Seven Network.