A major biosecurity failure likely led to an outbreak of white spot disease in Queensland that cost prawn farmers more than $40 million, Australia's inspector-general of biosecurity has found.

Helen Scott-Orr's report, released today, details a litany of failings in biosecurity that led to the outbreak of white spot disease in Logan River prawn farms in south-east Queensland, in October 2016.

Dr Scott-Orr said the failed import biosecurity system had allowed huge quantities of white spot-infected raw prawns to be sold in supermarkets.

She said there was proof fishermen were using the prawns as bait in the Logan River upstream from the affected prawn farms.

She described a systematic rorting of import conditions by a number of prawn importers to escape testing.

Dr Scott-Orr concluded the biosecurity risk of uncooked prawns had been poorly managed, and it had broader implications for Australian biosecurity.

She said there has been a 25 per cent reduction in front line inspection staff in the last five years, which is a critical weakness in confronting the challenges of increased imports of goods.

Biosecurity failing costs millions

The outbreak of white spot disease was first detected in October 2016 and confirmed on November 30.

Biosecurity authorities killed the prawns on all seven prawn farms on the Logan River, and emptied the ponds.

The cost has been enormous:

Logan River prawn farm industry production losses — estimated at $43 million in 2016-17

Logan River prawn farm industry production losses — estimated at $43 million in 2016-17 Federal Government assistance to control the spread of white spot disease — $22 million in 2017-18

Federal Government assistance to control the spread of white spot disease — $22 million in 2017-18 The Queensland Government spent $17 million on response and $9 million on follow-up measures

The Queensland Government spent $17 million on response and $9 million on follow-up measures Federal and Queensland Government assistance and reimbursement to industry of $21 million and $30 million in concessional loans.

"During this review, I found several deficiencies in the management of the biosecurity risk of uncooked prawn imports, with broader implications for Australia's biosecurity risk management more generally," Dr Scott-Orr said in the report.

She said the specific policy elements and their implementation had sowed the seeds of failure many years earlier, "while progressive and cumulative acts, omissions and systemic factors at many levels exacerbated risks over time".

Dr Scott-Orr praised the Department of Agriculture and Water Resources for acting swiftly since banning the imports in January, and putting in place testing measures for the future.

But she made several recommendations, and said the only way to improve biosecurity was with long-term adequate resourcing.

The recommendations include boosting funding, especially with imports of high-risk goods increasing.

Findings welcomed

Queensland prawn farmer Ian Rossman lost his entire stock through the outbreak of white spot. ( ABC News: Kristian Silva ) Queensland prawn farmer Ian Rossman, whose entire stock was wiped out, welcomed the findings but said he was concerned about future outbreaks of white spot.

"We are dealing with a virus, and the thing about a virus is it only takes a little bit of product to get into the wild, and there it starts," he said.

Mr Rossman said had been "very clear" to farmers that the disease had come from overseas imports.

However he said it was unlikely affected farmers would pursue compensation through the courts, because of a $20 million reimbursement package announced earlier this year.

Ponds on Mr Rossman's farm that once housed up to eight tonnes of prawns are now dry and covered in weeds, but he hoped to re-stock next year.

New prawn import restrictions

Once the finger was pointed at imported prawns, imports were suspended in January, and later resumed in July with new restrictions.

They included prawn testing prior to export, and sealed shipments that are now screened on arrival in Australia.

The federal Department of Agriculture and Water Resources has agreed to put in place the recommendations, including reviewing the various pathways for white spot disease to enter and establish in Australia.

The department said it had begun improved sampling for consignments of imported uncooked prawns.

The report recommended the department apply direct penalties for serious non-compliance.

It has also agreed to recommendations that it improve communication with industry about exotic aquatic diseases.