The iconic Sydney Opera House, defaced last year by anti-war protesters, will receive a A$9 million security upgrade, including digital surveillance cameras and new locks for its hundreds of doors.
Officials said today more and better trained security staff would be employed and tighter controls on vehicles, including new barriers to stop unauthorised vehicles approaching the building, would come into force over the next two months.
A new law, backed by fines of A$5,500, would making it a criminal offence to climb, damage or deface the building's sweeping sails.
"We are facing new threats, a new environment," opera house chief executive Norman Gillespie told reporters.
Two protesters opposed to the Iraq war painted a three metre (10 foot) high "No War" slogan in blood-red paint across the top of one of the opera house's white sails in March 2003.
The pair have been convicted of causing malicious damage but have yet to be sentenced. Armed state police began patrolling the opera house after the stunt.
New South Wales state premier Bob Carr said there were no plans to increase security for the nearby Sydney Harbour Bridge, because it was less vulnerable to attack, with the possible exception of September 11-style hijacked aircraft attacks.
"The danger to the bridge from anything other than a strike by a hijacked aircraft is less than the danger to any building," Carr told reporters.
Australia, which committed troops to the U.S.-led war on Iraq, beefed up security at key landmarks last year after anti-war protesters showed up the vulnerability of several tourist sites, including the opera house and Prime Minister John Howard's Sydney residence.