Pro-gun crossbench senator David Leyonhjelm's call for more Australians to carry guns has been rejected by the Opposition and Greens.

The Liberal Democrat has suggested that if more people had guns, someone could have stopped the hostage-taker in the Sydney siege.

Senator Leyonhjelm argues Australians should be allowed to carry concealed weapons, as in some states in America.

"What happened in that cafe would have been most unlikely to have occurred in Florida, Texas, or Vermont, or Alaska in America, or perhaps even Switzerland as well," Senator Leyonhjelm told the ABC's AM program.

"Statistically speaking" in those jurisdictions, "one or two of the victims" would have had a concealed gun, he said.

But Opposition Leader Bill Shorten bluntly rejected his views.

"I don't see how providing more guns into the population make us safer," Mr Shorten told AM.

"Our rate of gun deaths for the same population proportionately is far less [than America] and I do not see how putting more guns into the community makes us safer."

Mr Shorten would not say if he believed Australia's laws needed to be tougher, but he acknowledged "we've got to review that".

"One question here is are the laws adequate? The next question is are the laws enforced?" Mr Shorten said.

"We've got to learn the lessons but we've got to do it calmly. We owe that to the survivors and the victims of the Martin Place siege."

Former deputy prime minister Tim Fischer said it was "seductive nonsense" to suggest American-style firearm policies would be appropriate in Australia.

Mr Fischer backed gun control laws in the wake of the Port Arthur massacre.

"Debate will always go on in a good democracy but where it is built on a pack of lies from the NRA it should be dealt with swiftly," he said.

"It is seductive nonsense to say concealed gun laws would somehow work here in Australia."

Acting Greens leader Adam Bandt called the Sydney siege "Tony Abbott's Port Arthur moment" and said it should lead to tougher gun laws.

More guns increases likelihood of mass murder: Howard

Federal Attorney-General George Brandis said questions had been raised about how gun laws were enforced.

"It appears the gun [Man Haron Monis] held was a weapon that was banned as a result of the Howard government's changes in 1996, so the question is not whether the laws are tough enough but the way in which the laws are enforced," Senator Brandis said.

Former prime minister John Howard, who took on the gun lobby in 1996, said Senator Leyonhjelm was wrong to suggest Australia was a "nation of victims" because people could not properly protect themselves.

Mr Howard told The World Today Senator Leyonhjelm's views reflected a "simplistic and flawed analysis".

He said the guns laws introduced after the Port Arthur massacre made Australia a safer country.

He also said there was ample research evidence to show that gun-related homicides had fallen in Australia.

"Around the world, those laws are praised and seen as a model for other countries, struggling with gun-related violence, to emulate," Mr Howard said.

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He said he respected Senator Leyonhjelm's views on other matters, but he could not agree on the gun issue.

Mr Howard said the senator was misguided to think that more guns in the community would equate to a safer environment.

"It's just an exercise in logic to understand that the more guns there are in the community, the greater the likelihood of mass murder," he said.

Mr Howard said he did not believe there would be much community support for more lax gun laws.

"I don't think there's going to be a resurgence in attempts to roll back those laws. I'm confident that at both state and federal level, any attempt to roll back those laws would be resisted," he said.

Mr Howard said he still received feedback from many Australians and Americans telling him that his gun laws had made the community safer.

He said it was always a better option to have fewer weapons circulating in the community.

"You can never guarantee that a seemingly sane, calm person who's got a licence to hold a weapon won't at some point in the future go berserk and use it."