A Gold Coast couple who funded a "lavish lifestyle" peddling MDMA and cannabis on the dark web has been jailed after pleading guilty to drug trafficking.

Key points: Jonathon Grey ran a sophisticated drug trafficking operation that netted hundreds of thousands of dollars, the court heard

Jonathon Grey ran a sophisticated drug trafficking operation that netted hundreds of thousands of dollars, the court heard His wife Kathleen was not directly involved but "derived significant financial benefit" from the dark web trade

His wife Kathleen was not directly involved but "derived significant financial benefit" from the dark web trade The couple pleaded guilty to offences including drug trafficking and production

In 2017, the couple was listed among Australia's most-wanted criminals.

Jonathon Grey, who was the "principal" offender, was sentenced to nine years in prison for what Supreme Court Justice James Douglas called one of the "worst examples of high-level trafficking" he had come across.

Grey's wife, Kathleen Ann, was handed a six-year prison term for her subsidiary role.

The Brisbane court heard the couple trafficked drugs for a year to September 2016 and that it was a sophisticated commercial business, with Mr Grey's business profile on the online black market revealing more than 600 completed orders that exceeded $400,000.

Software was also used to "jumble" cryptocurrency transactions and encrypt conversations.

The total turnover was not known but Justice Douglas concluded it would have been "very significant".

The court heard the couple's family home was used as an "office" for the business, while a second property operated as a "grow house".

When police raided that property, they uncovered cannabis plants estimated to be worth more than $200,000 and about $20,000 worth of equipment.

The court heard Jonathon Grey also sourced drugs from the Netherlands through the post.

Officers also seized computers, a mobile phone and exercise books that contained details of addresses and tracking numbers of mailbags.

Justice Douglas said those records reflected Grey's "previous business experience".

More than $300k forfeited

The court heard he ran the business but that his wife was fully aware of the operation and "derived a significant financial benefit" from it.

Justice Douglas said he accepted Kathleen Grey only assisted her husband when asked but never visited the grow house or ordered drugs from overseas.

The court heard the Greys had a Porsche and BMW.

More than $300,000 was forfeited after the Crime and Corruption Commission launched criminal confiscation proceedings against the pair.

Kathleen Grey's barrister Lars Falcongreen said following that legal action, his client's anxiety levels "went through the roof" and she left for South Australia, joining her husband there.

The court heard the pair had two daughters and that being separated from them and each other in prison had been difficult.

"Unusual circumstances that both the mother and father are incarcerated," Mr Falcongreen said.

Jonathon Grey's defence counsel Colin Reid said his client, who previously had a significant cocaine addiction, was now contrite.

The couple pleaded guilty to several offences including drug trafficking and production.

Jonathon Grey will be eligible for parole after August 2021.

Due to time already served, Kathleen Grey will be eligible for parole in November.