Prominent Aboriginal health leader Donna Nelson is facing the prospect of 10 years in a Japanese prison if prosecutors get their way.

Ms Nelson, a longtime health advocate and community figure, is accused of smuggling two kilograms of methamphetamine into Japan.

Ms Nelson has maintained throughout her arrest, imprisonment and trial that she picked up the luggage in which the concealed drugs were later discovered from Laos on the request of her online romantic partner, a man known as Kelly, who told her it contained samples for his fashion business.

On Tuesday prosecutors called for a 10-year prison term and the equivalent of a $30,000 fine.

In January last year Ms Nelson was arrested at Narita Airport after narcotics were found hidden in a concealed compartment in the bottom of the case she carried.

In closing arguments this week, prosecutors seized on the fact Mr Nelson declared "business" as her reason for travel, and did not say at first that the bag was someone else's. Ms Nelson has said she believed at the time the bag was for Kelly's fashion business.

The ABC reports that the prosecution claimed Ms Nelson was "untrustworthy".

"If she had nothing to hide, why didn't she just tell the truth, and why didn't she tell customs that she was going to see her fiancé?," prosecutor Mr Ogata told the court.

Ms Nelson had previously told the court she fell in love with Kelly, who she met online, and that the pair had multiple video chats and corresponded often by text.

She has said that after multiple attempts to meet up fell through, Kelly booked Ms Nelson a flight to Japan with a three-day stopover in Laos, where an associate of his gave Ms Nelson the bag.

"She tried to illegally import the drug, and she was ready to receive cash, and a diamond ring and marriage," Mr Ogata asserted.

Ms Nelson was in tears, the ABC reports, as she told the judges and jury members she was innocent.

"I was tricked by Kelly to import methamphetamine," she said.

"If I had known or even suspected illegal drugs were in the suitcase, I would have never agreed to carry it."

Ms Nelson has told the court she put her belongings into Kelly's suitcase because she did not want to manage two bags for the flight, and as such did not think to declare the case as someone else's, particularly since she intended to marry Kelly.

She said she filled out "business" as the reason of her visit because she felt embarrassed.

"I ask you, please consider the case carefully, fairly," she pleaded to the judges.

Ms Nelson's defence told the court that she has had a long career as a community leader who worked to help those in need, including those addicted to drugs.

The defence said Kelly "skilfully" manipulated Ms Nelson, who was an innocent victim of a love scammer.

"Of course, she knows how devastating the drug is," lawyer Nishida Rie said, the ABC reports.

"She dedicated herself to protect kids and poor people from the drug.

"If she had known Kelly was a criminal, would she have sent her beloved granddaughters' picture to him?"