On 28 November 2022, the Director-General of the Australian Security Intelligence Organisation (ASIO) announced the lowering of the National Terrorism Threat Level from Probable to Possible. This was the first change to the Threat Level since it was raised to High or Probable on 12 September 2014, which was quickly followed by the first Appleby plot foiled on 18 September 2014, the Numan Haider stabbings on 23 September 2014, the Lindt Cafe siege on 15-16 December 2014 and the second Appleby plot foiled on 18 December 2014. ASIO had anticipated, accurately, that Islamic State’s transnational mobilisation would result in a far greater frequency of terrorist plots in Australia.
This table shows how many apparent terrorist plots (including foiled plots along with attacks that succeeded in harming people) Australia has experienced since the Threat Level was first raised in September 2014. I say “apparent” because some of these cases are unresolved. The overwhelming majority are now proven, but some are still before the courts (either criminal trials or coroners’ inquiries).
The lack of plots in the last year has been part of the reasoning behind ASIO’s decision, and reflects that the wave of plots associated with Islamic State has dissipated. Australia has experienced a surge in far-right violent extremism in recent years, as plots inspired by Islamic State declined, but the extreme-right threat has fortunately not made terrorist plots as frequent in Australia as they were at the peak of Islamic State’s global rise (2014-4017). However, apparent extreme-right plots contributed significantly to number of incidents in 2020 and 2021, and should not be overlooked (particularly with the Christchurch massacre tragically showing how much harm a single attack can cause).
|Apparent terrorist attacks and plots in Australia since September 2014|
(proven or alleged)
|Foiled terrorist plots|
(proven or alleged)
Note that these figures, based on public information, suggest ten terrorist attacks in Australia and 22 foiled plots since 2014, which is slightly inconsistent with ASIO’s statement that “[s]ince 2014, there have been 11 terrorist attacks on Australian soil, while 21 significant plots have been detected and disrupted.” I suspect that the difference is due to the ambiguity over which specific incidents ASIO has assessed as terrorist attacks occurring in 2021.
 At the time it was called the National Terrorism Alert Level (a system originally introduced in 1978 then altered in 2003), and it was changed from Medium to High, before the system and its categories were changed in 2015. However, Medium was essentially synonymous with Possible and High with Probable.
 For a complete list of all these incidents, with sources, see this table. For many incidents in Australia since September 2014 that resemble terrorism but were not treated as terrorism by the courts or coroners, see the discussion underneath the table in the same post. For some of the debates about whether events such as the Sydney Siege should be characterised as terrorism, see here, here, here and here.
 Note that for 2016 I have excluded one incident that the courts have treated as a terrorist attack, which was the firebombing of a Shia mosque (the Imam Ali Islamic Centre) in Melbourne on 11 December 2016. I am excluding it because:
- It did not injure or kill anyone, and therefore more clearly resembles the sort of ideologically motivated firebombings that do not usually result in terrorism charges (such as white supremacist Ricky White’s burning of a Church in 2016, or the Australian Nationalists Movement’s foiled plan to firebomb four Asian restaurants in 2004) rather than a clear terrorist attack.
- Several of the people responsible were part of the Federation Square bomb plot that same month, so including it would risk double-counting (by listing an activity that could arguably amount to part of the same plot).
- The Australian Security Intelligence Organisation did not appear to include the incident in its official figure of “seven attacks” in Australia between September 2014 and April 2019.
 One was extreme-right.
 This excludes the Christchurch massacre, perpetrated by an Australian white supremacist in New Zealand, killing 51 people and wounding many more. It is excluded because it did not occur within Australia, but should still be considered the most important terrorism event for Australia in 2019.
 One was extreme-right.
 ASIO has stated that two terrorist incidents occurred in Australia in 2021. I suspect that one of the events I have listed as a plot is listed by them as an attack. I am sticking to my original figures to avoid double-counting and because I think ASIO may use a broader definition than I use of what constitutes an attack.
 Two were extreme-right.