Justice Minister Michael Keenan has reassured Australians about the adequacy of security measures in place to protect them from possible terrorist attacks during the festive season.
Speaking after a car bomb explosion in Canberra overnight and this week's deadly truck attack in Berlin, Mr Keenan said authorities remained concerned about an attack on home soil.
"People should be reassured we have given our police agencies, intelligence community the powers they need to protect them and the resources they need to protect them," he said.
"There's literally no other place on the face of the globe that's done as much as Australia to mitigate the threat of a terrorist attack.
"There's no guarantee something won't occur here and people need to be mindful if they see something that doesn't appear right, call the national security hotline.
"We're prepared to deal with this and I hope Australians take that reassurance into the Christmas season."
Authorities in major cities around the world have been stepping up security following the deadly truck attack at a busy Christmas market in Berlin, where 12 people died and 48 others were injured.
Security has already been ramped up to protect cricket fans at the Adelaide Oval, with concrete blocks installed around the venue.
Meanwhile, local Christian groups are reviewing their security after a suspected car bomb exploded outside an Australian Christian Lobby office in Canberra on Wednesday night.
In Sydney, police are confident they have adequate security in place for the millions of people celebrating Christmas in Australia's biggest city.
"There has been no specific threat, however the public can be assured NSW Police has security plans in place for events across the festive period," a spokeswoman said.
Thousands are expected to attend Christmas services at Sydney's famous St Mary's Cathedral and St Andrew's Cathedral in the city's CBD on Sunday.
"We don't comment on specific security measures, but in these times all Australians should be vigilant and report any suspicious activity to police or the National Security Hotline 1800 123 400," a spokesman for the Anglican Church said.
A spokeswoman for the Catholic Archdiocese declined to comment about whether extra security would be in place at St Mary's on Christmas Day.
Mr Keenan said it "makes sense" for organisations holding events where large crowds are expected "to take sensible precautions".
"We work very closely with our state and territory counterparts to ensure that's the case," he said.
