A Canadian drug mule will spend four and a half years in an Australian jail after admitting she tried to smuggle 30 kilograms of cocaine into Sydney on a cruise ship to clear a A$20,000 debt.

Isabelle Lagace, 29, arrived in Sydney on the Sea Princess in late August 2016, having boarded the ship in England before travelling to Ireland, the US, Bermuda, Colombia, Ecuador and Chile.

Australian Border Force officials found a suitcase containing about 30kg of cocaine in her shared cabin, later estimated to be worth up to A$21.5 million.

"I have embarrassed my family, my friends, myself," Legace, right, said.

Late last year, Lagace pleaded guilty to importing a commercial quantity of a border-controlled drug but claimed to have been given an ultimatum about clearing a A$20,000 debt to an unnamed person.

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She also claims she began to receive threats - although she refused to provide any details - and was told her debt would be cleared if she provided a bag to another passenger to be filled with a substance.

In evidence presented to the NSW District Court on Friday, Lagace admitted she took full responsibility for her actions.

"I have embarrassed my family, my friends, myself," she said.

"It pains me to know that my defining years of womanhood will be spent in prison halfway around the world."

Judge Kate Traill said the defendant had a job, an apartment and a support network when she decided to go through with the plan.

"There were many choices open to her to pay the debt," she told the court.

The judge also rejected as "vague and imprecise" the woman's claims of a threat, noting she was non-responsive and evasive when asked to elaborate.

But Lagace had good prospects of rehabilitation and a solid support network, Judge Traill said.

She imposed a sentence of seven years and six months, however, after the non- parole period was backdated to her arrest date Lagace will likely be released in February 2021.

Lagace's said she was angry to have been involved with the "dirty, filthy drug trade".

"This will haunt me for the rest of my life."