Tasmanian Alkaloids was singled out in an Oklahoma District Court judgement as the main supplier of raw opium to Johnson & Johnson and other manufacturers at the height of an opioid addiction epidemic in the United States.

The court this week ordered Johnson & Johnson to pay $847 million to carry out an abatement plan in Oklahoma - a decision the company intends to appeal.

Tasmanian Alkaloids, along with Noramco, were subsidiaries of Johnson & Johnson from the 1980s until their sale in 2016, and were a part of the company at a time when opioids were being aggressively marketed in the US.

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The judgement, from District Court Judge Thad Balkman, said Tasmanian Alkaloids "cultivated and processed opium poppy plants to manufacture narcotic raw materials that were imported into the US to be processed and made into APIs (active pharmaceutical ingredients) necessary to manufacture opioid drugs".

Oklahoma state solicitor Brad Beckworth reportedly said the crisis "began in Tasmania and New Jersey with Johnson & Johnson".

Sassafras poppy farmer Rick Rockliff said Tasmanian farmers should not be held responsible in any way for the opioid crisis.

"I think with them trying to blame Tasmanian farmers is absolutely ridiculous. Tasmanian Farmers and Tasmanian Alkaloids operated completely within the law," he said.

"We provide legal pain control for many people around the world that needed it. Some people abused it, and I can't see how they can possibly hold anyone in Tasmania responsible for that."

Mr Rockliff said "common sense would prevail" and the case wouldn't have a negative impact on the state's industry".

Poppy production in Tasmania peaked in 2012 when the scale of the addiction crisis became widely known, prompting former US president Barack Obama to release a white paper into the issue.

Since then, poppy production reduced from 30,000 hectares to about 12,000 hectares, and the number of growers reduced from 850 to 400.

Poppy Growers Tasmania found production has now effectively plateaued after prices fell sharply.

Tasmania is believed to produce about 50 per cent of the global demand for alkaloids, however exact figures are difficult to determine due to tight regulations around the industry. The United States remains the largest market.

Tasmanian Alkaloids was bought by SK Capital Partners in 2016, and remains one of the three Tasmanian producers along with Sun Pharmaceutical and TPI Enterprises.

Poppy Growers Tasmania could not comment as the matter remains before the courts.

Implications from the ruling could also roll over to other US states.

The court found there was no opioid epidemic in Oklahoma until the mid-1990s, before Johnson & Johnson started marketing and promoting opioid drugs containing oxycodone, codeine, tapentadol, tramadol and the synthetic fentanyl.

The company also supplied APIs to other drug manufacturers.

Johnson & Johnson's marketing campaign included literature funded by the company in medical journals, material from patient advocacy groups, paid speakers, networking dinner among doctors and unbranded marketing material.

Some tactics included "emotional selling", using the term "pseudoaddiction" to describe patients exhibiting signs of addiction by saying they were instead suffering "undertreatment of pain" and needed more opioids.

Sales representatives were also urged to avoid "addiction ditch" references, and instead focus on the positives of pain treatment.

Judge Balkman said Johnson & Johnson played a clear role in the opioid crisis.

"The increase in opioid addiction and overdose deaths following the parallel increase in opioid sales in Oklahoma was not a coincidence; these variables were 'causally linked'," he said.

Between 2011 and 2015, 2100 people in Oklahoma died of unintentional prescription opioid overdose.

In 2015, more than 326 million opioid pills were dispensed in the state - enough for every adult to have 110 pills each.

In 2017, 4.2 per cent of babies born under government-funded SoonerCare health program in Oklahoma were suffering withdrawal from drugs.

Johnson & Johnson has sought to defend its former affiliate Tasmanian Alkaloids, while at the same time signalling its intention to appeal the court's ruling.

In a statement, Johnson & Johnson said the companies complied with international and federal regulations and quotas "at every stage of the supply chain".

"These included importation and manufacturing quotas established by the U.S. Drug Enforcement Administration and FDA," the statement reads.

"The state did not contest that these affiliates complied with the regulations at all times.

"Importantly, as suppliers, these former affiliates played no role in the manufacturing, sales or marketing of the finished products of other DEA-regulated manufacturers.

"Oklahoma law bars liability for the supply of these raw materials, and a comprehensive federal regulatory program authorized and painstakingly regulated the importation, manufacture and sales of those materials."