Federal Labor has slammed big tobacco’s push to overturn Australia’s vaping ban, saying the government should not be listening to an industry that “only cares about creating new markets and increasing their profits”.

But vaping proponents have dismissed what they say is a “pervasive myth” that the push for e-cigarettes is a big tobacco conspiracy, saying the industry plays only a minor role in what is largely a grassroots consumer movement.

Guardian Australia revealed this week that Philip Morris International, the tobacco giant, is lobbying government MPs against Australia’s effective ban on vaping, as it seeks to grow sales of its e-cigarette products to 42% of global revenue by 2025.

The company’s lobbying has been hidden from the public because of Australia’s weak lobbying oversight regime, which is completely blind to corporations that use their own in-house lobbyists to influence government policy.

Quick Guide Political lobbying in Australia: the basics Show What do lobbyists do? Lobbyists attempt to influence government policy or decisions on behalf of either a client or their own organisation. Ethical lobbying is a valuable and important element of a healthy democracy. It helps those who have a stake in government policy to convey their views and expertise. There are two broad types of lobbyists: third-party lobbyists, who are engaged as consultants; in-house lobbyists, who work directly for corporations or interest groups. Who hires lobbyists? For many Australians, lobbying conjures images of powerful corporations working to sway politicians behind the scenes. There is a truth in that. The big banks, mining and energy giants, pharmaceutical companies, casinos, Amazon, Google and Facebook all engage lobbyists. But lobbyists also work on behalf of not-for-profits and community groups, including for veterans, social workers, aged-care staff, school principals and environmental organisations. What is the lobbyist register? The lobbyist register is the public's only window into the world of lobbying. It's a publicly available online list of lobbying firms, individual lobbyists and their clients. The register was a huge step forward when it was introduced in 2008, but remains frustratingly opaque. It doesn't tell us who is lobbying whom, about what, or when. Compare that with the ACT, where lobbyists are required to file quarterly reports on their activities, or NSW, where ministers are required to publish their diaries. The federal register is also completely blind to the activities of in-house lobbyists. What is the lobbyist code of conduct? The code tells lobbyists how they must behave when approaching the government and is designed to maintain ethical standards. But the code is not legislated and has no real teeth. It goes largely unenforced and the punishments are weak. The worst sanction available to authorities is removing a lobbyist from the register. The US and Canada have fines or jail terms for law breaches. Who keeps an eye on lobbyists? Federally it's the prime minister's department that loosely oversees lobbying. It takes on a largely administrative role, rather than an investigative or regulatory one. Its core job is to maintain the register and communicate the code's requirements to lobbyists. It lacks independence, relies on reports of bad lobbying and rarely, if ever, takes enforcement action.

The health minister, Greg Hunt, remains resolute that the ban will not be lifted.

“The overwhelming medical advice and evidence is that it’s likely to lead to the uptake of smoking and we cannot support that,” a spokesman said this week.

Pressure from within Coalition ranks, however, last month prompted the government to announce a new inquiry into the safety and efficacy of e-cigarettes.

The deputy opposition leader, Tanya Plibersek, said Labor accepted the existing expert advice that e-cigarettes should be banned “until evidence of their safety, quality and efficacy can be produced”. Plibersek accused the government of outsourcing “public health policy to big tobacco lobbyists”.

“Instead of listening to big tobacco, Scott Morrison and Greg Hunt should listen to their own experts and maintain the ban on nicotine e-cigarettes,” Plibersek told Guardian Australia.

“Big tobacco isn’t moving into e-cigarettes because it cares about people’s health, they’re doing it because their existing customers keep dying from terrible smoking-related diseases. Big tobacco only cares about creating new markets and increasing their profits.”

But backers of vaping say the tobacco industry plays a small role in promoting vaping. One of the key voices calling for e-cigarette legalisation, a University of New South Wales’ associate professor, Colin Mendelsohn, said it was a “pervasive myth” that big tobacco was behind vaping products.

“It would be a public health tragedy if the uptake of vaping was undermined because of the false belief that vaping was a tobacco industry plot,” he said. “Vaping is a far safer alternative to smoking and has helped many millions of smokers to quit.”

Mendelsohn said vaping devices had been invented outside of the industry and were a disruptive force to existing players. He said tobacco companies were now simply trying to catch up, and that their share of the vaping market remained low.

The academic is a tobacco treatment specialist who chairs the Australian Tobacco Harm Reduction Association, which had vaping companies as its founding sponsors.

The Therapeutic Goods Administration classes nicotine as a dangerous poison and it is an offence to sell the chemical unless a permit has been issued by state or territory authorities. This ban has not stopped the uptake of vaping in Australia.

Australia’s position on e-cigarettes is at odds with other comparative developed nations. New Zealand, Canada and the US all allow vaping. Its proponents point to a report from the Royal College of Physicians in the UK which found it had “huge potential to prevent death and disability from tobacco use”.

But all of Australia’s health bodies say evidence about the long-term effects of vaping, and its value as a quitting aid, is not yet available. The National Health and Medical Research Council, the chief medical officer, the Australian Medical Association, the Royal College of General Practitioners and others all say more long-term research is needed to understand the potential harms.