NSW residents are alert and alarmed about the prospect of a terrorist attack, with some avoiding public places and transport out of fear.
Nearly 14 per cent of people sometimes avoid public places and events because of fear of terrorist attacks, a study has found.
About one in 20 has changed their use of public transport in recent times and one in five has deferred or changed plans for overseas travel.
The most recent terrorist attack in NSW was more than 30 years ago, according to the government white paper on counterterrorism. Since 2001, 38 people have been prosecuted in Australia for terrorism offences and 20 convicted.
The study leader, Garry Stevens, said for some people the threat of terrorism was always in the back of their mind.
''We know there are some people who tend to think about it a lot, and that's people with a higher background level of anxiety, and people in certain demographic groups,'' said Mr Stevens, a clinical psychologist and lecturer at the University of Western Sydney.
People who were more likely to avoid certain areas tended to have lower levels of education or believed an attack was more likely, according to his research, which forms part of a wider study into Bali bombing survivors funded by the Australian Research Council.
The study, published in BMC Public Health, found people who had changed their use of public transport were more likely to live in highly accessible urban areas rather than rural areas.
Mr Stevens said fears about terrorist attacks could be used productively, not only to help protect people but also to help them deal with their fear.
The study found 45 per cent of people had either moderately or extremely increased vigilance for suspicious behaviours, while nearly 40 per cent had learnt their building's evacuation plan and 20 per cent had an emergency family contact plan.
''What we are finding overall is some of the people who have engaged in preparation, who have a plan, they have less ongoing anxiety,'' he said.
He said from a public health perspective it would be best if people were provided with more specific, useful information.