AUSTRALIAN travellers who fall ill or are injured in the US are being caught out by sky-high medical bills, with some having to fork out more than the cost of a house.

That's according to claims paid by travel insurance company Cover-More in the past year, with those needing lengthy hospital stays the worst affected.

It doesn't bode well when a visit the ER for a minor cut that may need a few stitches could end up costing $7000, and a simple case of appendicitis requiring a two-night stay in a New York hospital could cost more than $75,000.

Meanwhile, if you're unlucky enough to be involved in a car accident in the US and require intensive care, it could set you back $300,000.

On the worst end of the scale, two tourists who required month-long hospitalisation for a kidney condition and a bowel obstruction each racked up bills nearing the $1 million mark.

Cover-More spokesman Zac Brookes said Australians are still being caught out as the US medical system is so different – and complex. Those who are uninsured can face a nightmare financial scenario.

"We believe that about 25 per cent of Australian travellers head overseas without travel insurance," Mr Brookes said.

"If an Australian traveller finds themselves, uninsured, in a US hospital, it could quickly evolve into a terrifying situation where they see their medical bills quickly start running in to the tens of thousands of dollars and their credit card limits and those of their fellow travellers start to be severely tested."

He warned the price of treatment can vary dramatically depending on which hospital you visit.

"There is no price regulation or limits to how much a medical provider can charge for their services in the United States, unlike here. You will even find major differences between what two hospitals will charge for the same treatment in the same city.

"For example, there could be as much as $40,000 difference in the amount charged for a two night stay in hospital, depending on which New York hospital you are admitted to.

"You're charged for everything. Your medical bill will usually contain an itemised bill for every single treatment and item of medication you receive, even a simple headache tablet.

"It is a complicated system that ultimately requires a profit motive."

In 2012, Cover-More paid more than $16 million in claims to the US alone.

"That figure is a combination of the high cost of medical care in the US plus the fact that more Australians are heading there, attracted by competitive air fares and the recent strength of the Aussie dollar," he said.

