Australia has been labelled a country of “disarmed victims” by crossbench senator David Leyonhjelm in the wake of the deadly siege in Sydney.

The pro-gun Liberal Democrat wants to reopen the debate on self-defence and access to weapons in the wake of the fatal siege, which saw 17 hostages held for 16 hours by gunman Man Haron Monis.

Senator Leyonhjelm told ABC Radio that those trapped within the Lindt café were left helpless, as carrying weapons is not allowed under Australian law.

“It would have been illegal for them to have had a knife, a stick, a pepper spray, a personal taser, mace, anything like that for self-defence,” he said.

“I regard that [as] an absolute travesty. To turn an entire population into a nation of victims is just unforgiveable in my estimation."

Senator Leyonhjelm said such an event was less likely to happen in the United States, as it was probable that some hostages would be carrying a weapon.

“That nutcase who held them all hostage wouldn't have known they were armed and bad guys don't like to be shot back at,” he said.

Senator Leyonhjelm has long been an advocate for firearms, resigning from the Liberal Party in 1996 following John Howard's crackdown on guns following the Port Arthur massacre.

His office has reportedly received death threats over his comments.

His senior advisor Helen Dale told SBS that she and her colleagues had received multiple "threatening" messages, described in a Twitter post on Thursday.

Anti-gun people: calling people with different views on firearms laws and threatening to assassinate them does not help your cause. #auspol — Helen Dale (@_HelenDale) December 17, 2014

Senator Leyonhjelm also used social media to address the threats.

Interesting. Anti-gun fanatics are threatening me and my staff with violence. Maybe they'd just prefer to ban disagreement. — David Leyonhjelm (@DavidLeyonhjelm) December 17, 2014

Urgent review commissioned

His comments follow confusion over the gunman’s access to weapons, with Prime Minister Tony Abbott saying that Monis was licensed to have a gun.

Mr Abbott’s statement has since been disputed by NSW Police.

Mr Abbott has also commissioned an urgent review into the siege, to be conducted by his department chief and NSW Premier Mike Baird's most senior adviser.

He said it was vital the review looked into how Monis, who was known to security agencies, was on bail, was on welfare and able to access a gun.

Opposition Leader Bill Shorten meanwhile has dismissed the call to loosen laws regulating guns, stating "I don't see how providing more guns into the population make us safer".

Mr Shorten said that compared with gun deaths in America, Australia had proportionally far fewer fatalities.

Acting Greens leader Adam Bandt has also dismissed the push by Senator Leyonhjelm.