It comes as the bitter political fallout continues over revelations senior One Nation figures James Ashby and Steve Dickson lobbied America’s National Rifle Association (NRA) for $20 million in funding, and discussed trying to undermine Australia’s strict gun controls with NRA officials.

In 2017, there were an estimated 3.6 million firearms in Australia, compared with 3.2 million in 1996 - the year of the Port Arthur mass killings. In 1997, after former prime minister John Howard’s successful guns buyback, there were an estimated 2.5 million firearms in the country.

The startling figures are contained in a report, Hunters and Collectors: Gun use and ownership in Australia, by left-leaning think tank The Australia Institute.

It is the second report on gun ownership and the political strategies of Australia’s gun lobby released by the organisation this week, amid growing unease about the role of gun lobbies in Australia.

The first report, Point Blank: the covert lobbying of Australia’s gun lobby, urged Australian political parties to rule out taking donations from the gun groups.

It showed that since 2011, firearms companies and members’ associations had donated more than $1.7 million to Australian politicians, the vast majority of which went to Katter’s Australia Party, and the Shooters, Fishers and Farmers Party.

The second report, seen by The Age and The Sydney Morning Herald, shows that while the number of licensed firearm owners fell from 1.2 million to 0.8 million between 1997 and 2016, each owner now has more firearms - from an average 2.1 per owner to 3.9 per owner.

After Port Arthur, Mr Howard banned semi-automatic firearms and introduced a National Firearm Agreement that won widespread praise both at home and internationally.

But since then, according to the Australia Institute reports, which were commissioned by Gun Control Australia with contributions from GetUp!, there have been concerted efforts to undermine the spirit of the agreement.

In 2017, the Sporting Shooter’s Association of Australia’s Victorian chapter openly bragged that its lobbying efforts had helped reduce the number of proposed changes to the National Firearm Agreement.

A review of the Victorian agreement had proposed sweeping changes to the accord, including the introduction of 28-day waiting periods on permits.

In a statement, SSAA Victoria chief executive officer Jack Wegman said more than six industry bodies swung into action.

“We had been lobbying Commonwealth and State governments alongside our key industry partners throughout the NFA battle,” Mr Wegman said. “But when the updated NFA was released, with all of its potentially disastrous changes, we knew we had to step it up a notch.

“We developed a submission with the support of a professional lobbyist and then began working behind the scenes on politicians.

"We approached people as individual organisations and together, under the CFCV [Combined Firearms Council of Victoria] banner, to arrange face-to-face meetings, deliver our submission and educate non-shooting politicians who could influence the police minister.”

In the end, there were just two changes to the agreement.

According to the The Australia Institute, pro-gun lobbying has become more mainstream - including in federal parliament.

The Sporting Shooters Association of Australia sponsors shooting events at Parliament House for politicians and press gallery journalists, which The Australia Institute suggested played a role in lobbying sympathetic politicians to the cause.

In 2016, Nationals senators Brigid McKenzie and John Williams crossed the floor to vote with then Liberal Democrats Senator David Leyonhjelm’s motion to end an import ban on the lever-action Adler shotgun (Nationals ministers Fiona Nash, Nigel Scullion and Matt Canavan were not in the chamber during the vote).

“As the Nationals come under pressure in rural seats, especially from the Shooters Party, they may be tempted to change policy on guns,” The Australia Institute discussion paper said.