Colombian police have said they were tipped off Australian woman Cassandra Sainsbury could be carrying drugs out of the country, adding the cocaine's intended destination could work against her.

Cassandra Sainsbury was arrested at the international airport in Bogota. ( AP: Colombia's National Police )

Ms Sainsbury was arrested on April 12 at Bogota's international airport after an X-ray machine detected 5.8 kilograms of cocaine hidden in 18 different packages stashed in her luggage.

The 22-year-old was preparing to board a flight to London on her way back to Australia.

Her family contends she was set up, but Colombian police said her arrest was indistinguishable from a growing number of drug cases involving foreigners.

"In this case, and with information we previously received, we received [information] about a citizen of this nationality [Australian], with an identification, could possibly be a drug mule," anti-narcotic police ports and airports director Jorge Mendoza said.

"In going through security, we found that she had 18 packets inside her luggage, which even before opening it, we found it covered in plastic."

Mr Mendoza said he was confident the seizure would lead to jail time, and said the cocaine's intended destination could also affect Ms Sainsbury's sentence.

"Depending on the qualities, but we believe that the maximum could be 20 years, and the punishment for the quantity could be between eight to 12 years," he said.

"Let's keep in mind that of the countries in the world, Australia is the one with the highest per kilogram of cocaine.

"This cocaine that the traveller carried was possibly worth about $US1 million."

The case has garnered media attention in Australia and her family has raised more than $4,000 online to fund her defence.

'She has her ups and downs'

Joanna Adams, the daughter of the lawyer representing Ms Sainsbury, told ABC's AM program her father had given the family some free legal advice.

"She [Ms Sainsbury] has her up and downs, and some days she's good and some days she's very bad," Ms Adams said.

Cassandra Sainsbury is being held at El Buen Pastor (The Good Shepherd) Women's prison in Bogota. ( Flickr CC: District Women's Secretariat )

"He [Ms Adams' father] has been able to give the family some free legal advice into her situation."

Ms Sainsbury worked as a personal trainer in Adelaide and is a former volunteer firefighter. According to her sister Khala, she was in Colombia on a working holiday.

Khala told The Australian newspaper that while in Colombia, her sister went with a male friend she met before traveling to South America to buy headphones for her upcoming wedding party.

The merchandise was purchased from a contact in a pre-wrapped package, her sister said.

Ms Sainsbury has been transferred to a women's penitentiary in Bogota.