"It's my fault Shanese is in trouble, being honest in my [police] interview cast blame on her," she said.

"People in jail call you a dog. But we are still sisters and I don't think anything will ever change that."

The Koullias sisters, who grew up in Callala Bay on the NSW South Coast with third co-offender, Cody Ronald Ward, were charged over their involvement in a $17 million drug ring masterminded by Ward and run from Callala Bay.

On August 4 in Nowra Local Court, Patricia Koullias, 22, pleaded guilty to six counts of supplying a prohibited drug and participating in a criminal group.

At her sentence hearing on October 21 she told the court she had helped her sister package drugs and deliver them to the post office.

Patricia said before her involvement in the drug ring began, she lived at Quakers Hill with her boyfriend and took drugs on a regular basis.

Xanax, Valium and other "downers" were her drugs of choice during the week, and on the weekends she used MDMA, LSD - "anything, really".

When the relationship ended in December 2018, Patricia said she struggled to find the money for rent and drugs. She claimed around that time her sister approached her with the offer of work packing and posting drugs.

Police say Ward imported the drugs under a number of pseudonyms, collected the packages from a variety of post offices on the South Coast before the drugs were repackaged and posted at a number of different Australia Post post boxes in the Shoalhaven.

It is reported drugs including cocaine, amphetamine, MDMA and LSD were sold over the dark web, and customers paid using cryptocurrency.

Patricia said she would drive from Quakers Hill to Callala Bay for two to three hours of work a week, and received between $300 and $400 on each occasion for her help packaging and posting drugs.

She said she was able to take as much Xanax as she needed.

She also admitted she pocketed 114 tabs of LSD and took them to her home in Quakers Hill.

"I thought I could give it to people for money, and we'd have a party," she said.

Patricia said she did not have any contact with Ward, or anyone involved in the criminal group other than her sister.

She did acknowledge, however, that she had known Ward as a child.

The three co-offenders all grew up in Callala Bay.

Patricia said she did not have a relationship with her father prior to her arrest, and has a strained relationship with her mother.

She said since her arrest, however, her father had been "wonderful".

"He has been beautiful, a wonderful support to me," she said.

"[Before the pandemic] he visited every weekend and spent the whole day here.

"He's very excited to have me stay with him when I'm released. I have a support network now, I know my dad will help and advise me if I fall on hard times again."

Her defence argued that Patricia's role in the drug ring was "peripheral and lowly" and she made full admissions to police upon her arrest.

She said she was deeply sorry for her actions.

"I know saying sorry can't change the actions I've already done," she said.

"But I am sincerely sorry and ashamed of what I've done, and the impact it has had on those around me."

Shanese Koullias is due to have her sentencing hearing in Nowra District Court on Friday, October 23. Cody Ward is due to have his sentencing hearing in Nowra District Court on Tuesday, October 27.

Police caught them after an extensive nine-month surveillance operation, which included listening devices.

The trio will be sentenced at the Downing Centre on November 27.