Former prime minister John Howard has warned it would be a "huge mistake" to water down Australia's gun laws amid debate over a controversial shotgun.

Key points: John Howard warns Government against allowing importation of new shotgun

John Howard warns Government against allowing importation of new shotgun Shotgun has fast firing rate and eight-shot magazine capacity

Shotgun has fast firing rate and eight-shot magazine capacity David Leyonhjelm defends decision, saying the user creates the danger, not the gun

The Federal Government has agreed to allow the importation of the Adler lever-action shotgun in a year's time, pending a review into the system.

Gun control advocates say the rapid-fire weapon from Turkey should be permanently banned because of its fast firing rate and its eight-round capacity.

Mr Howard, who introduced a ban on automatic and semi-automatic weapons following the 1996 Port Arthur massacre, said he did not believe Australians wanted to see weaker restrictions.

"If the Government ends up letting this in, and not treating it as I think it should be on the evidence available to me at the moment — treated as akin to an automatic or semi-automatic — then I would be very critical of that, certainly, and that would be a huge mistake," Mr Howard said at a Sydney function organised by Gun Control Australia.

"I don't think a great majority of Australians want to see a weakening of gun laws.

"They think it's something we got right and I think we should keep it that way."

The Coalition temporarily suspended imports of the Adler weapon in July as part of a firearms review triggered by the Martin Place siege.

It has now agreed to a 12-month sunset clause on that suspension, following a deal struck with NSW Liberal Democrat senator David Leyonhjelm on a migration vote.

Importer Robert Nioa with the Adler shotgun. ( ABC )

Mr Howard said while the Federal Government was free to make deals to get legislation through Parliament, he disagreed with the senator's stance.

"Any winding back of the laws concerns me, and I'm critical of any winding back. I really am," he said.

"If you exercise common sense you have seen a demonstrable dividend out of these laws."

Mr Howard introduced the ban in 1996, when gunman Martin Bryant killed 35 people and wounded 23 in Port Arthur.

The Turkish-made shotgun uses a lever action to load cartridges into a barrel, but Gun Control Australia claims it is on the verge of being a high-capacity pump-action shotgun.

'It's the person that makes danger'

Carolyn Loughton, who lost her 15-year-old daughter Sarah in the 1996 massacre, said the standards Mr Howard set should not be watered down and called for the weapon to be banned.

She told the conference she has undergone 30 surgical operations after being wounded in the attack.

"I was 40 when this happened and this doesn't go away. There's another 18 survivors out there, and I can assure you I only know some of them but they are also going through absolute hell with this," she said.

Senator Leyonhjelm, who has advocated for gun laws to be changed, said any further restrictions could trigger an angry response from recreational shooters.

"Australia's shooters are angry at being targeted. They were targeted when John Howard was prime minister as sort of a collective responsibility for what happened at Port Arthur and of course they weren't," he said.

The NSW senator said lever-action shotguns have been available in Australia for over a century, and he would be disappointed if a review into the National Firearms Agreement recommended they should be banned before the sunset clause expires.

"Once a person is safe to have a gun, it really doesn't matter what kind of gun they've got. If they're safe, it's safe," Senator Leyonhjelm said.

"It's not the gun that makes the danger, it's the person that makes the danger, and blaming a gun for the danger is the wrong way around."