(CNN) On the long, bloody list of US gun violence , it would barely be a blip, but the killing of four people in northern Australia has caused shock in the country most often held up worldwide as an example of effective gun control.

At least four people were killed in the city of Darwin and several injured when a gunman opened fire with a pump-action shotgun late Tuesday night in several different locations, police said. A suspect was apprehended soon afterward, and has been identified as 45-year-old local Ben Hoffmann, according to CNN affiliate 9 News . Hoffmann was on parole at the time of the killings.

It is the worst spree shooting in Australia since the 1996 Port Arthur massacre , which resulted in the country radically overhauling its gun laws, and the worst gun-related crime since a murder-suicide last year in Western Australia, in which a grandfather killed his entire family and himself

"Four killed in Darwin massacre," read the headline on the NT News, a Darwin paper, while the Herald Sun, based in the southern state of Victoria, splashed with "Shotgun rampage."

Prime Minister Scott Morrison described the incident as a "terrible act of violence" and said his thoughts were with citizens of the Northern Territory "and the tight-knit community in Darwin."

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Global example

Australia has long been seen as a potential model for the US on gun control for the effectiveness of its response to the Port Arthur massacre.

Following the shooting, in which 35 people were shot by a lone gunman armed with a military-style semiautomatic rifle in the Tasmanian tourist spot, then-Prime Minister John Howard brought in strict gun control laws , ending a previously lax approach to weapons in the country. Rapid-fire rifles and shotguns were banned, licensing tightened, and more than a million firearms were collected and destroyed.

Since then, multiple other gun amnesties have been held and tens of thousands of other firearms handed-in.

In the decade leading up to the 1996 massacre, more than a 100 people had been shot dead in various shooting sprees. In the years following reform, the risk of dying by gunshot in Australia fell by more than 50% -- and stayed there. Suicide by firearm -- one of the leading causes of gun death in the US -- was also reduced by almost 80% in the decade after Port Arthur.

"Today, there is a wide consensus that our 1996 reforms not only reduced the gun-related homicide rate, but also the suicide rate," Howard wrote in 2013

In the wake of the Christchurch massacre in March this year, New Zealand followed Australia in banning assault rifles and introducing strict new gun laws

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Push for change

The rarity and shock of Tuesday's attack shows just how effective Australia's laws have been in preventing mass shootings. By comparison, already this year the US has seen 11 mass shootings at least as deadly as the Darwin incident, according to the Gun Violence Archive

In the most recent, 12 people were gunned down in Virginia after a man opened fire indiscriminately before being shot dead by police.

Despite the apparent success of the Australian reforms, there has been increased pressure in recent months to relax the country's strict gun laws.

This has largely come from fringe right-wing parties and politicians, as well as an increasingly active gun lobby. In March, Morrison, the prime minister, defended Australia's gun laws after it was alleged One Nation, an anti-immigration party founded by Pauline Hanson, had sought donations and guidance from the US National Rifle Association (NRA)

"Reports that senior One Nation officials courted foreign political donations from the US gun lobby to influence our elections and undermine our gun laws that keep us safe are deeply concerning," the Prime Minister said at the time. "Thankfully, our (government) has also made laws to criminalize taking foreign political donations so foreign lobbyists cannot seek to influence our politics."

Representatives of One Nation denied seeking funds from the NRA, and accused Al Jazeera, which exposed the meetings through an undercover report, of "skullduggery."

The revelations came after Tim Fischer, a former Australian deputy prime minister who along with John Howard crafted the country's tough gun laws, warned that "NRA-inspired" gun groups were attempting to water down or overturn the regulations.

"America's guns laws were weakened through a gradual process." George Rennie, an expert in Australian politics at the University of Melbourne, wrote last year . "This involved the patient undermining of the popular will through the passage of favorable laws in state legislatures -- the blocking of others -- and a continuing narrative that linked guns with freedom and gun control with an evil or 'nanny' state."

"The Australian gun lobby has learnt from this American example, and its methods emulate it," he added.