British American Tobacco used freedom-of-information laws to seek access to six Cancer Council Victoria files, arguing it was in the public interest to expose to scrutiny the raw material used to underpin its plain packaging position.

The council opposed in all six cases, saying the data was either gathered on a confidential basis for the purpose of public health, or was outdated or incomplete and its release was contrary to the public interest.

The non-profit health group also argued there could be no limit to what the tobacco company could do with the material from the Australian Secondary Students' Alcohol and Drug Survey, which includes information that may have commercial value as a marketing tool to attract young smokers.

BAT maintains it sought the documents only to review the effectiveness of plain packaging laws.

It is not allowed to conduct its own research on schoolchildren because of a prohibition on commercial surveys in schools.

Last year, Fairfax Media revealed BAT had previously used the Freedom of Information Act to obtain Cancer Institute NSW research into adults' attitudes to smoking, which was subsequently used by the tobacco company in Britain to contest plain packaging laws.

The institute had effectively handed the company access to millions of dollars' worth of taxpayer-funded research believing it was legally obliged to do so. The Victorian council has spent thousands of dollars to prevent a similar outcome.

The secondary students' drug survey collected information from thousands of Australian students (aged 12 to 17) about their gender, postcode, pocket money and what sort of school they went to. They were asked about their smoking and drinking habits, how they accessed cigarettes and which brands were "cool".

Associate Professor Victoria White, a senior researcher at the Cancer Council's Centre for Behavioural Research in Cancer, told the Victorian Civil and Administrative Tribunal the release of answers relating to children's tobacco use could be used in targeted price discounting to attract adolescents.

The centre's head, Melanie Wakefield, said participation in the survey was consented to by schools, parents and students on the basis identifying details would be confidential, and that releasing this data meant it would be unlikely they would participate in future studies.

Supreme Court Justice Greg Garde, the president of VCAT, refused access to all but one set of documents sought by the tobacco company, in a judgment published on Tuesday.

He approved release of data relating to the National Tracking Survey of Smokers and Recent Quitters becauses the study was complete and the final data set already widely available.

But Justice Garde found releasing any of the other material, including the secondary students' drug survey documents, would be contrary to the public interest.

He accepted evidence the drug survey had included information communicated in confidence to the researchers and that release of data from the 2011 and 2013 surveys could identify participants.

Both parties have 28 days to appeal the decision.

Cancer Council Victoria chief executive Todd Harper was "delighted" by the outcome but said he was taking advice from lawyers about the one released document.

"The moves by British American Tobacco to gain sensitive data about children is reprehensible and we are delighted the VCAT has ruled so comprehensively against sensitive children's data being handed over to agents of British American Tobacco," Mr Harper said.

"Parents, teachers and children had trusted the Cancer Council to keep that data confidential, we take that trust very seriously, but if we were forced to hand that data over to the tobacco industry there would be no restrictions on how they would use it."

A British American Tobacco spokesman said it was reviewing its legal options.

"We strongly refute the spurious allegations levelled by the CCV. This has always been about reviewing data to determine whether plain packaging was working or not," he said.

"While we are disappointed that access was only granted to one of the six documents sought, for the majority of documents that access was refused, it was only because that research was incomplete."