Labor says the Turnbull government should ban a new version of a rapid-fire shotgun from being imported into Australia while a review considers claims the gun type seriously undermines post-Port Arthur gun control laws.

As reported by Guardian Australia, a new five-cartridge version of the controversial Adler 110 lever-action shotgun is being imported into Australia, sidestepping a year-long federal ban imposed on an Adler 110 that fired seven rounds.

The gun control lobby says new “lever-action” shotgun technology means the guns are very similar to rapid-fire pump action shotguns, and should be subject to similar restrictions. Shooting organisations strongly dispute this.

The acting opposition spokesman on justice, Graham Perrett, said the Turnbull government should immediately include the modified five-shot Adler 110s in its temporary ban.

In July as orders for the original version of the Adler 110 were pouring into a Brisbane gun retailer, the former prime minister, Tony Abbott, said imports of the weapon would be banned for at least six months.

A month later, after an angry backlash from gun owners and some self-confessed “blackmail” in the Senate by David Leyonhjelm – who bargained with his vote on unrelated asylum-seeker legislation – the Coalition promised the import ban would be lifted after 12 months.

The government said the ban would allow state and federal governments to consider future imports as part of a review of the national firearms agreement, struck after the 1996 Port Arthur massacre. The review was ordered after last year’s Martin Place siege.

The original version of the Adler lever-action shotgun being imported was capable of firing seven shots in rapid succession, something Gun Control Australia said gave it similar fire power to pump-action shotguns, and would have been available in most states under the most common and least restrictive gun licence.

But last month the same Brisbane retailer began offering a slightly modified version, one that fires five 12-gauge cartridges rather than seven.

A spokeswoman for the justice minister, Michael Keenan, confirmed the new gun was not covered by the ban, which applied only to shotguns with a magazine capacity of more than five rounds.

According to Gun Control Australia’s vice-president, Roland Browne, making the Adler available as a “category A” firearm “would … completely undermine the national firearms agreement. It puts rapid-fire shotguns in the hands of the general community, which is exactly what the agreement was designed to avoid.”

Given the events of the past week ... now is not the time to erode or undermine John Howard’s tough gun laws Labor's Graham Perrett

And the GCA president, Sam Lee, said whether the gun could fire five or seven cartridges made no difference because it was “the new lever-action technology that causes alarm”.

“As gun technology is updated, our laws should be reviewed to ensure that it keeps up with the advances in technology,” Perrett said.

“Until the national firearms agreement review is complete, the Adler 110 lever-action shotgun should not be allowed into the Australian market, modified or otherwise … Given the events of the past week, domestically and abroad, now is not the time to erode or undermine John Howard’s tough gun laws, which are respected around the world.”

In its submission to the review GCA argues that if the Adler is imported as a category A firearm, available to everyone with a gun licence, “it will have a devastating impact on Australia’s strong gun laws and pull Australia back to the pre-Port Arthur days”.

It cites gun enthusiasts as saying the Adler was a “game-changer” and it “comes as close as possible to being a pump-action shotgun without being a pump action”.

But in its preliminary submission to the review, the Sporting Shooters Association said it was incorrect to claim a lever-action shotgun was “verging” on being a pump-action gun.

“A firearm cannot ‘verge’ on being a particular type of firearm. It either is, or it is not. Its mechanism defines the firearm; it cannot ‘sort of’ be like another,” the association’s submission says.

It also rejects the conclusion that the post-Port Arthur gun laws have lowered Australia’s levels of gun crime.

“It is clear that public safety is almost always threatened by the unlicensed person with the unregistered firearm in the rare case where firearms are involved,” it says, and claims the national firearms agreement “has also been found to have no large effects on reducing firearm homicide or suicide rates”.

The National party is also deeply concerned about any new gun ownership restrictions and the review poses an early test of the relationship between the prime minister, Malcolm Turnbull, and his Coalition partners.

Commonwealth and state ministers and attorney generals will consider the review’s findings in November and make recommendations to the prime minister and premiers before a council of Australian governments meeting early next year.