Australia's anti-terrorism measures have undoubtedly affected freedom of expression. An obvious example of this is the sedition laws. Despite significant public opposition, these laws were "updated" in late 2005. Broadly described, the sedition laws prohibit speech that urges the violent or forceful overthrow of the government, violent or forceful interference in elections and inter-communal violence, as well as speech urging others to assist an enemy of Australia. These laws clearly criminalise particular kinds of speech and dissent, namely the kinds most commonly associated with revolutionary politics and insurgency.

Another case demonstrating the impact on freedom of expression was the banning of two books because of their perceived links to terrorism. In July 2006 the Classification Review Board refused classification to the Islamic books Join the Caravan and Defence of the Muslim Lands on the basis that they promoted and incited terrorism. Prompted by these cases (in particular by the fact that the books were not initially banned but were only banned upon review), the Coalition government passed laws changing the classification scheme to explicitly ban material that advocates terrorist acts. Relying on extremely broad definitions for "advocates" and "terrorist acts", these new laws have the potential to significantly restrict political, religious and ideological expression.

But Australia's counter-terrorism laws and policing have also indirectly affected the freedom of expression of particular religious and ethnic groups. While this impact has not been as overt as the examples above, it has arguably been much more widespread.

Australia's national security hotline is an example of this. For years a pervasive advertising campaign has encouraged the public to report anything and everything suspicious. At the same time, Muslim communities have frequently been depicted in the media and by politicians as being inextricably linked to terrorism, thereby casting those communities as inherently suspicious. Exacerbated by a widespread community backlash against Muslim communities after 11 September 2001, anecdotal reports suggest that this has led to many cases of Muslim individuals being reported to the hotline simply for expressing certain political and religious views. Knowing that they are regarded with suspicion, people are forced to stifle their public speech to avoid being the subject of a report to the hotline. This has no doubt had a chilling effect on speech and political/religious communications in Muslim communities.

The types of evidence relied on by authorities in prosecuting terrorism cases has also sent the message that there are some things that certain communities cannot speak about. The case of Abdullah Merhi, who is currently facing terrorism charges, is an example of this. In a bail application hearing, the prosecution read transcripts of a conversation between Merhi and a co-defendant in which Merhi allegedly talked about retaliating against John Howard for taking the lives of other Muslims (in the Iraq war) and about sending a "message back" to avenge Muslim deaths. He also allegedly raised questions about whether such retaliation falls within the scope of the Islamic faith. These musings were relied upon by the prosecution as evidence that Merhi and his co-defendants were involved in a group and that the nature of that group was "jihadi". The message of this is clear: it is not acceptable to speculate, however vaguely, about revenge on the prime minister or about the scope of one's religion in relation to acts of violence, particularly if you are Islamic.

This evidence sends a particularly threatening message to communities that have already found themselves the subjects of official scrutiny in relation to national security. The listing of terrorist organisations, and the laws around terrorist organisations more broadly, have caused certain ethnic and religious groups to come under official scrutiny. Specifically, Islamic, Kurdish, Tamil and Somali communities have all found themselves under the watch of counter-terrorism authorities. Given the types of evidence that have been used in cases such as Merhi's, this scrutiny has a stifling and silencing effect. For fear of being prosecuted, community members are compelled to ensure that they do not possess certain kinds of political/religious material and to ensure that they do not engage in certain kinds of political/religious conversation or associations. In addition to the obvious injustice of this, when communities are compelled to stifle their expression insofar as it relates to liberation struggles or civil wars in their homelands, the effects will be deeply felt.

It is true that for many people, Australia's anti-terrorism legislation does not prevent them speaking their minds, accessing the books they want to read, pondering the scope of their religion's doctrines, or possessing a particular party or group's political materials. But for many others Australia's anti-terrorism measures have directly and indirectly attacked their freedom of expression. While the impact of the sedition laws is still in the realm of the hypothetical (there have been no prosecutions to date), the silencing of certain types of political speech along religious and ethnic lines is very much here and now. While it is perhaps not the most widely discussed consequence of our anti-terrorism laws, its effect on impacted communities is likely to be profound.

Marika Dias is Convenor of the Federation of Community Legal Centres' Anti-Terrorism Laws Working Group.