Canada and Australia have both featured prominently in the Islamic State's online diatribes, in which the group urges its global followers to kill.

But the similarities don't end there.

They are both parliamentary democracies whose leaders have vocally and materially backed international action against the Islamic State, with small but devoted extremist networks at home and some dozens of citizens currently fighting with jihadist groups in the Middle East. They both have tight gun laws and have ramped up security at their parliaments and government buildings in response to the current heightened threat.

Foreign Minister Julie Bishop's response to the assault overnight on Canada's war memorial and parliament in Ottawa highlighted the likenesses.

"For quite some time, these murderous, brutal terrorist organisations have been speaking about attacks on those sorts of institutions and in those sorts of countries, including Canada, Australia, the United States, any country that opposes their ideology, any country that embraces freedom and tolerance," she told the ABC.

Canadian national security expert Wesley Wark, who spoke to Fairfax Media by phone, has painted a picture of a society whose values, outlook and response to the global phenomenon of the Islamic State are strikingly similar to Australia's, right down to its parliamentary security measures.

It invites the question: how did the attack happen and could a similar one occur here?

Like Canberra, Ottawa's security changed dramatically in the years after September 11, 2001. In Ottawa's case, this meant armed police outside the building and armed guards inside.

"The parliamentary precinct is a place that was already pretty heavily protected for a legislature in a democracy," said Professor Wark, who is based at the University of Toronto and has previously been an adviser on national security to the Canadian government.

He is familiar with Ottawa's parliamentary building. As he describes it, the man was able to crash through the initial layer of security but could not make it far once he was inside.

The gunman approached through the entrance reserved for MPs and staff.

"He basically burst through the door, ran up the stairs, possibly shot one of the guards at that initial desk, and then made his way down an adjacent corridor where he was trapped by a combination of police armed response and the security guards within the parliamentary building," Professor Wark said.

"It is physically possible to crash through. It's never been done before but the response by all accounts was very rapid and very professional."

Canberra's parliamentary guards do not carry weapons but since a recent security upgrade, the Australian Federal Police, who are armed, have taken over security inside the building as well outside. AFP officers stationed outside the building carry long-armed weapons.

Speaker Bronwyn Bishop told MPs on Thursday morning that the recent upgrades had included "enhanced perimeter controls and armed response capability" to stop the kind of attack that happened in Ottawa.

Ms Bishop stressed that Australia's parliament and its perimeter are "very different to the design of the Canadian parliament. She added there were "a number of layers of layers of security measures" to protect occupants.

The two countries' deployments to Iraq are also strikingly similar. Like the Abbott government, Stephen Harper's administration has authorised sending fighters for bombing raids – though these have not yet begun – and special forces advisers.

Professor Wark said Canada had debated whether the deployment raised the domestic terrorism risk at home, but that public support for an intervention was clear.

"All the polling suggests the majority of Canadians are in favour of this," he said. "I suspect these attacks will ever further solidify Canadian support for engaging in the military campaign against ISIL. But people will ask questions about whether we are prepared for reprisal attacks."

Per capita, Australia has more of its citizens fighting in the Middle East with extremist groups – and likely more supporters at home – than Canada.

Professor Wark says that according to the best guess of experts, about 30 Canadians have gone to Syria or Iraq to fight with the Islamic State and other extremist groups, next to the roughly 60 Australians that ASIO says are there now.

This is the second attack in a week after a suspected jihadist ran down two soldiers with a car on Monday, killing one of them. This man was on a "no-fly list" in Canada amid fears he planned to travel to the Middle East.

Like Australia, Canada is grappling with the additional risk posed by frustrated would-be fighters who are forced to stay at home – an unavoidable consequence to the widely-supported policy of cancelling passports of such suspects.

"It's speculation that outside experts and indeed government officials have made that … because (the man in the driving attack) was prevented from travelling abroad to engage in an operation … he decided that being trapped in Canada, he was going to carry out his attack here," Professor Wark said.

Both countries have foiled major plots in the post-9/11 period, Canada's most prominent being the "Toronto 18", in which the conspirators planned to storm parliament and behead the prime minister and also attack the national broadcaster and state intelligence buildings.

There hasn't been anything on that scale recently. Like Australia, the fear now is very much about low-tech attacks – particularly by extremists who might never have travelled or gained serious training but are being influenced by events in the Middle East.

"We've been worried about the foreign fighter phenomenon as I know you have in Australia. Maybe we've been over-worried about that and lost sight a little bit of the home-grown terrorism dimension."