However the majority of plots in their advanced stages were foiled, according to police.

The country has survived four terror attacks — three in New South Wales and one in Victoria — and narrowly escaped 11 others since September 2014.

Twenty-three people have been convicted of terrorism offences in Australia in the last four years, according to Australian National Security.

A recent US Homeland Security report revealed that Australia ranked equal-third among Western nations as a target for Islamic State-inspired terror attacks.

2014

September Numan Haider 18, Endeavour Hills, was shot and killed after stabbing two police officers in Endeavour Hills.

September More than 800 police and ASIO officers, supported by armoured cars, sniffer dog teams and helicopters, carried out pre-dawn raids in 15 suburbs in Sydney and Brisbane. No arrests were made in Brisbane but 15 people were detained in Sydney in 25 raids. Government officials revealed that the plan was to kidnap random members of the public, behead them on camera and then release the video of the killings.

December Convicted criminal Man Haron Monis takes 18 hostages at the Lindt cafe in Sydney's Martin Place. After 16 hours, two hostages — cafe manager Tori Johnston and barrister Katrina Dawson — are killed. Monis is killed in a shoot out.

Man Monis was shot dead by police following a 16-hour hostage siege.

Counter-terrorism police in Sydney arrest two men, charging one with possession of documents designed to facilitate a terrorist attack.

2015

January The national terror threat for all police is raised from medium to high.

February Police arrest and charge two Sydney men with planning to carry out an imminent terrorist attack. A machete, a hunting knife and a flag associated with Islamic State were among items seized in the raids.

April British police confirm a teenager from northern England has been arrested in connection with an alleged plot to target an Anzac memorial service in Australia.

Five teenagers were arrested during counter-terrorism raids across Melbourne's south-east.

May A Melbourne teenager is arrested for building explosive devices in preparation for a Mother's Day terrorist attack.

April Three young men are arrested in a co-ordinated series of raids over planning to kill a police officer during the 2015 Anzac Day commemorations.

August Seven young Australians are stopped on their way to join terrorists in the Middle East.

September Victoria Police establishes a new counter-terrorism squad as part of a more "sophisticated" approach to tackling the threat, with a specific focus on preventing radicalisation.

October A 15-year-old with a Middle Eastern background shoots dead a NSW police civilian employee. He is killed by officers on the scene.

Selina Cheng at the memorial for her late husband Curtis Cheng. Photo: NSW Police

2016

May A Sydney man who had allegedly bid to join extremists in Syria, was accused of planning an imminent lone-wolf terror attack in Australia. The teenager had allegedly scoped out the Parramatta court complex, Garden Island Navy Base and the Victoria Barracks.

June A Sydney teenager allegedly planned a "serious" terror attack — potentially involving a knife — on a police officer in NSW. The 17-year-old was charged with a "terrorism-related offence" after police were alerted to a series of social media posts where the teen had threatened to kill a police officer.

August Operation Fortaleza disrupted an alleged domestic terrorist attack at an undisclosed location in Melbourne, potentially involving improvised explosive devices.

October Two teenagers purchased knives and were en route to behead a stranger in Sydney's Bankstown before they were arrested in a laneway behind a Bankstown mosque. NSW Police deputy commissioner Catherine Burn claimed it was the "11th imminent attack ... we have prevented in this country".

December Seven arrested and five remain in custody after police stopped a potential multimode attack at Federation Square, Flinders Street Station and St Paul's Cathedral, Melbourne. Those in custody are all men. Chief commissioner Graham Ashton said the attack, using "explosive devices" was "mostly likely" to be carried out on Christmas Day. Apart from explosives, police also suspect guns and knives may have been used.