Australian Border Force (ABF) and Commonwealth prosecutors have been relying on evidence provided by Australia's biggest tobacco company to charge black market traders.

Key points: Border Force has used British American Tobacco's labs to test seized black market products

Border Force has used British American Tobacco's labs to test seized black market products A WHO treaty limits tobacco companies' involvement with law enforcement to only what is strictly necessary

A WHO treaty limits tobacco companies' involvement with law enforcement to only what is strictly necessary A British American Tobacco spokesman says it did not charge the Government for its services

ABF has handed seized tobacco to British American Tobacco (BAT) to be tested in its laboratory, an ABC investigation has revealed.

BAT has analysed the product and then provided documentary or expert evidence which has then been produced in court.

It raises questions about independence and integrity and potentially breaches a major global agreement.

The World Health Organisation treaty limits tobacco companies' involvement with law enforcement to only what is strictly necessary.

Tobacco companies argue they are being good corporate citizens by helping in the fight against the black market trade, but anti-smoking advocates say they are just protecting their bottom line.

These cigarettes were found by police in Melbourne in April this year. ( Supplied: Department of Immigration and Border Protection, file )

Earlier this week, the ABC revealed big tobacco companies were propping up law enforcement by providing high-level intelligence and paying for surveillance technology.

There is a government agency called the National Measurement Institute that provides analysis for law enforcement.

A spokesperson for ABF said it used the agency "where possible", but conceded there were times it had relied on the tobacco companies.

"There are instances in which tobacco companies have provided assistance in identifying counterfeit or illicit tobacco and have supplied statements for court proceedings," the spokesperson said.

The Commonwealth Director of Public Prosecutions represents the agency in most court matters and, in a statement, said it "relies on evidence obtained from investigative agencies".

"The identification of suitable experts is normally a matter for the relevant investigative agency … [and] is fully disclosed during the course of any prosecution."

BAT confirms laboratory services loaned to ABF and others

When contacted by the ABC, BAT confirmed it had loaned its facilities to more than one law enforcement agency.

"That was about establishing whether the products were tobacco products, which is important to know before they can proceed with prosecution," BAT spokesman Josh Fett said.

"We were pretty happy to help out, because the tobacco black market is huge."

He said BAT approached law enforcement with the offer, and did not charge them for the service.

"I certainly don't think there's any conflict … it's up to law enforcement agencies whose service they use and in these cases it was us," he said.

"We have a clear interest in combating and assisting anyone that's willing to fight criminals selling illicit tobacco in Australia, we don't have any issue with helping anyone we can."

Tobacco company 'drafts warrant request'

The ABC has obtained more documents showing the level of the tobacco giants' involvement in police operations.

An Imperial Tobacco PowerPoint presentation boasted its company and Philip Morris "assisted NSW Police to conduct raids" at six locations in Sydney in 2015.

The raids purportedly seized $60,000 worth of black market tobacco. ( ABC News )

"Our role … provide a brief of evidence to police," it read.

"Draft warrant request.

"Store seized product."

Imperial Tobacco analysed the product for police. ( ABC News )

Imperial Tobacco emailed the presentation to New South Wales Labor MP Paul Lynch in October 2015.

"I was astonished I must say, I had no idea that the cooperation between a large tobacco company and the police was as intense as it is," he said.

"This is a relationship that's way too close."

He said NSW police needed to own up about the level of cooperation they had with the tobacco companies.

"The police have to be entirely transparent about what exactly they're doing and upfront about the reality that tobacco companies are making profit out of their activities," he said.

"Police need to behave as the police and conduct their own investigations, prepare their own briefs and execute their own warrants.

"That's not a function of the state that should be farmed out to private corporations."

Police, Imperial Tobacco decline to answer questions

New South Wales police declined to answer the ABC's questions about the cooperation and declined to specifically comment on the tobacco industry.

They sent a statement saying they regularly worked with many industries.

"Their involvement is non-operational," the said.

"Just as a member of the community may provide information to law enforcement about crime impacting the community, so too will industry."

Imperial Tobacco Australia also declined to answer the ABC's specific questions.

It also sent a statement, in which it says [the industry] will continue to provide intelligence on the black market.

"Imperial Tobacco Australia makes available to relevant enforcement and prosecuting authorities our personnel who hold expert knowledge in respect of tobacco products.

"It is our view that the cooperation of our industry with enforcement and prosecuting personnel is vital to combatting serious and organised crime that is responsible for much of the trade in illicit tobacco.

"The documents you refer to were designed to give transparency and shine a light on this alarming issue."