Anti-smoking campaigners have accused the Coalition of secretly giving tobacco giants access to a parliamentary inquiry, a move they say undermines more than 15 years of precedent to protect public health.On Monday, representatives from tobacco company Philip Morris appeared before a Senate committee considering the illegal tobacco trade in Australia.Chaired by South Australian Liberal senator Leah Blyth, the committee also heard from anti-smoking campaigners, health groups and Australian Border Force, but Labor, the Greens and the Australian Council on Smoking and Health raised concerns that executives from cigarette manufacturers were allowed to give evidence in a closed session in Canberra.The committee published a full program for Monday’s hearings, but did not list evidence from Philip Morris or any other “in camera” – or private – session.Labor senator Jana Stewart and Greens senator Jordon Steele-John objected to the in-camera evidence by representatives of Philip Morris on Monday afternoon.

The health minister, Mark Butler, wrote to Blyth on Friday last week, reminding the committee of Australia’s obligations under a World Health Organization agreement on tobacco control, which requires public officials to protect health policy from interference from the tobacco industry and associated interests.Health Department guidance suggests Australian public officials, including members of parliament, should only interact with executives and lobbyists from tobacco manufacturers “when and to the extent strictly necessary” to effectively regulate smoking.The department also stresses interactions should be conducted transparently.“I would strongly advise against the committee inviting representatives that undermine this obligation,” Butler wrote to Blyth and the Senate president, Sue Lines.Stewart told the hearing efforts by public officials to be “cautious about any kind of influence or advice” from big tobacco companies were wise.

Later, Steele-John confirmed the private hearing had taken place and promised to release a transcript of the evidence.He said in a public session: “We have just taken evidence in camera from Philip Morris.I shared with them during our exchanges my opposition to their presence in this inquiry as witnesses.”Australian Council on Smoking and Health chief executive, Laura Hunter, said she was “concerned that individuals or organisations with links to the tobacco industry have been invited to participate in this inquiry”.“We recognise the committee may wish to hear from a range of stakeholders,” she said.

“But the tobacco industry is not a neutral stakeholder.It is a commercial actor whose profits depend on the continued sale of a product that kills Australians every day – and whose interests are directly affected by the outcomes of this inquiry.”Hunter said the presence of individuals from big tobacco companies did not strengthen decision-making, “it compromises it”.Guardian Australia has contacted the company and Blyth for comment.Lung Foundation chief executive, Mark Brooke, told the hearing tobacco companies had used obfuscation and denial of health harm for at least 50 years.

“You only have to look at the tobacco companies giving evidence before the US Senate, denying lung cancer in the ‘60s and ‘70s to play it out,” he said.“It’s fair to say big tobacco says things like ‘we want to un-smoke the world’ but then challenges every meaningful attempt by governments, not just here in Australia but around the world, to cease production or sales of their products.”Cancer Council Australia chief executive, Jacinta Reddan, said it had been 16 years “since big tobacco had a platform” in federal parliament.She pointed to the World Health Organization’s framework convention on tobacco control, article 5.3, which is designed to stop interference in public health policy from cigarette and e-cigarette manufacturers.

“We’re very concerned that they were given that opportunity behind closed doors, away from the scrutiny of the Australian public,” Reddan said.Assistant minister for customs, Julian Hill, called on Coalition senators to explain the secret hearing.“Australians should be shocked and outraged that today the committee chose to get secret evidence from big tobacco,” he said.“They’re quick to give comment when it suits them, and yet they want to skulk in in secret to a parliamentary inquiry when not.”