Accused Australian drug smuggler Cassie Sainsbury is reportedly under pressure to inform in return for a reduced jail sentence in Colombia.

The 22-year-old is facing 20 years in a Colombian prison after 5.8 kilograms of cocaine was allegedly found inside 18 headphone cases in her luggage at El Dorado International Airport in Bogota last month.

News Corp Australia says prosecutors will not agree to a plea bargain to substantially reduce her sentence unless she gives them details of who arranged the drug deal.

AAP