Prime Minister Tony Abbott said on Friday that Canberra could be a potential target for a terrorist attack, with discussions about targeting "government people" and "Parliament" intercepted by security forces.

University of Sydney government and international relation's senior lecturer Justin Hastings said Canberra would always have a higher risk of terrorism compared to other cities.

"There's also a lot of symbolic [buildings] in Canberra. That being said, the geography of Canberra means it's actually not easy to stage certain kinds of attacks as it would be in a more densely populated city," he said.

Dr Hastings said given Canberra's low-density population it would be difficult to inflict a large death toll on the population, unlike an attack in Sydney or Melbourne.

"Terrorists are more likely to live there in the first place and if you just want to kill someone it's easier to kill them there than in Canberra. If you want to kill lots of people, attacking a high traffic area in Sydney or Melbourne might make more sense," he said.

Dr Hastings said the increased terror alert level and recent terrorism raids in Sydney and Brisbane should not change Canberrans day-to-day behaviour.

"When you change you're behaviour, they're able to affect our way of life in Australia without doing anything, and changing our behaviour won't increase [our safety]," he said

"The optimal solution for the average people in Canberra is to be cogniscent of it but in general, just live your life."

ANU's Australian Centre for Military Security and Law visiting professor and former military intelligence officer Clive Williams said a small-scale attack could have wide-reaching consequences.

"If you could get into even 50 metres or 100 metres of Parliament House that would be seen as symbolically an attack on Parliament and that would attract more attention ... even if it didn't do very much damage," he said.

"With a terrorist attack, they don't have to be successful in terms of activating a device, it's just the intent to do it and the publicity associated with that, which might be useful for them.

"You can't rule out someone as a lone attacker putting together a vehicle bomb and coming to Canberra, but I think it would be an unlikely scenario," he said.

A number of government institutions and organisations refused to comment on whether or not they had increased security at their ACT buildings as a result of recent terrorist activity.

The Defence Department announced it had increased the security alert level at all its bases and establishments, including those in the ACT, to a level consistent with the national terrorism public alert level.

The Australian Federal Police, the Australian War Memorial, ASIO and a number of embassies also all refused to comment on whether they had increased their security as a result of the terror alert level increasing.

A Canberra Airport spokesman said there had been no additional increases to the airport's security.

Additionally, no changes to security are planned for the ACT Legislative Assembly building in London Circuit, but members and staff will be contacted next week regarding security procedures.