Less than half an hour later, Australia's Department of Foreign Affairs and Trade received its first call from a concerned member of the public, watching the horrifying news unfold. They had two relatives in Las Vegas. Were they OK?

It's one of the first questions the federal government is asked whenever there is an international crisis or emergency: are there any Australians involved?

The media and public expect answers quickly, even when the scale of an incident is huge, as in Las Vegas, where 58 people were killed and almost 500 injured. Yet by breakfast time on Tuesday, Foreign Affairs Minister Julie Bishop was able to say she was not aware of any Australian casualties "at this stage".

How does the government know this?

Unfortunately, given the frequency of terror attacks, natural disasters and political upheavals, DFAT has plenty of experience in responding to crises.

In 2016-17, it had more than 1800 so-called "whereabouts" cases due to the London and Nice terrorist attacks, the attempted coup in Turkey and deteriorating security situation in South Sudan. It has a permanent 24/7 emergency line – which also handles more routine issues like lost passports – that can be expanded for major incidents.

On Monday afternoon, within half an hour of that first phone call, DFAT in Canberra made contact with its Los Angeles consulate-general, which is responsible for Las Vegas. By 6pm, Australian diplomats in the United States were calling local hospitals and police to see if any Australians had been caught up in the shooting. The British and Canadian consulates were also contacted to see if any dual nationals were involved.

As Bishop told ABC TV: "There will be an ongoing process of seeking to contact all Australians who might or have been in the vicinity," (made easier by those who had registered their details with the government's Smartraveller website).

Meanwhile, Australian officials were flown from Washington DC to boost numbers on the west coast. By lunchtime on Tuesday, three Australian diplomats were in Las Vegas following up on unaccounted for Australians. As of Saturday, it was understood no Australians had been harmed.

DFAT's efforts in Las Vegas come as it released a report on the help it gives Australians "experiencing difficulty" overseas. Australians continue to be enthusiastic travellers, taking more than 10 million trips in 2016-17 – a number that has grown by about 25 per cent over the past five years.

The report notes that most travelling Australians who have a problem deal with it themselves. But about one in 1000 who are overseas at any given time seeks help from the government.

In recent years there has been an ongoing campaign from DFAT to limit the frivolous and downright ridiculous consular inquiries it receives. This includes a man who asked the Bangkok Embassy for money to pay for a prostitute. Or the people who want DFAT to feed their pets or point them to a pub playing the State of Origin.

This week, DFAT also issued a fresh warning to travellers, urging them to take out comprehensive insurance and read the fine print before going overseas. A recent survey found almost 90 per cent of travellers were not sure about what countries their insurance covered, while 87 per cent did not know whether riding a motorcycle overseas would be OK.

Melbourne nurse Hannah* knows the consequences of motorbike use first-hand, after riding one during a holiday to Malaysia in July. "I thought, I'll be fine," she recalls.

She was wearing a helmet and had travel insurance, but no motorbike licence, which meant when she came off and "pretty much landed on my face", she wasn't covered.

On top of the trauma of an accident that knocked her unconscious, Hannah and her partner had to pay thousands of dollars to fly back early to Australia. And, once home, she was hit with a $25,000 dental bill (and more excruciating pain) to deal with the five teeth she lost.

Three months on, she has a simple message: "I would just suggest not to get on a motorbike if you don't have a licence."

Because she was at fault, Hannah didn't even think to ask Australia's High Commission in Malaysia for assistance. But there are plenty of other people who are calling on the Australian government for help.

Over the past five years, diplomats have been faced with a growing number of arrests, deaths and hospitalisations. Between 2012-13 and 2016-17, arrest cases jumped from 1136 to 1641, hospitalisations increased from 1372 to 1701 and deaths from 1247 to 1653.

In part this can be attributed to the rise in Australians heading overseas. But Bishop is also calling for Australians to be as "self-reliant as possible": to take out the right insurance, give itineraries to someone at home, register with Smartraveller, respect the customs and security situation of the country you are visiting and see a doctor before you go.

Or as DFAT warned in its report: "Although we are proud of the level of assistance we can offer, there is no legal right to consular assistance and no one should assume that assistance will be provided."

*Surname not included.