Australians see Islamic State as the biggest threat to the nation, with one-third of people concerned about refugee hordes, global research shows.

Terrorist atrocities concerned 59 per cent of Australian respondents who took part in a Pew Research study, taken before last Saturday's terror plot raids across Sydney.

Refugee arrivals are also a major concern, with 33 per cent of those surveyed seeing it as a major risk to Australia.

Australians are concerned about IS terror with 59 per cent of respondents in a Pew Research survey nominating it as an issue (Melbourne teenager Jake Bilardi pictured with IS militants)

One third of Australians are worried about refugee arrivals (Christmas Island vessel pictured)

Australians are almost as worried about IS terrorism as people in Israel, where 63 per cent of respondents were scared of Islamist extremists killing civilians.

Terrorism is an even more significant concern in the United States, Britain, France and Germany, the Washington DC-based think tank's research found.

Refugee arrivals are another major international worry, with Canadians even more concerned than Australians, after their Prime Minister Justin Trudeau settled 25,000 displaced Syrians.

However, Australians were actually more concerned about the economy, with 42 per cent of respondents nominating it as an issue despite the last recession occurring 26 years ago.

Climate change was also a major concern, with 58 per cent nominating it as a problem.

The Pew Research survey of 42,000 people in 38 countries was taken between February and May, well before raids in late July across Sydney that saw two Lebanese father-and-son duos arrested and accused of plotting to bomb a passenger plane.

Australians see IS terror as the No.1 threat, as do people in the U.S., Britain and France