Footy security beefed up as terror risk level raised

Three major footy finals will be subject to Australia's new security measures today after the nation was put on a high terrorism alert for the first time.

The decision to raise the threat level from medium to high yesterday follows a spike in "chatter" detected in a sixfold increase in counter-terrorism operations during the past year.

While authorities do not believe a terrorist attack is imminent, they have intelligence there are people within the community who have the intent and capability to mount attacks.

NRL and AFL finals in Perth, Townsville and Sydney are expected to undergo new security measures on Saturday. They are the second lot to be played under the high threat rating after two games in Melbourne and last night.

Security will also be increased at airports, ports, military bases, government buildings and large public events.

NSW police intend focusing their efforts on popular landmarks such as the Sydney Harbour Bridge, and "soft targets" such as shopping centres.

Outgoing ASIO director-general David Irvine says the heightened security threat could manifest itself in another Bali bombing-style attack.

But the greater likelihood is "lone actors" using firearms at mass gatherings or in public places such as shopping centres.