The assessment, in the Australian Security Intelligence Organisation's annual report to Parliament, also reveals Australia's right-wing extremists, much like the Islamic fundamentalists they loathe, draw inspiration from overseas via the internet.

''There has been a persistent but small subculture of racist and nationalist extremists in Australia, forming groups, fragmenting, re-forming and often fighting amongst themselves,'' the report states.

The appraisal also states there has been a recent rise in anarchist or ''anti-fascist'' groups, with the ideologically-opposed groups coming into conflict.

''Where such confrontations have occurred, the 'anti-fascists' have outnumbered the nationalist and racist extremists and police intervention has been required,'' the report states in its ''Australia's Security Environment'' section.

The report reveals ASIO - whose budget has grown by almost 500 per cent since 2001 and will next year move into a half-billion-dollar Canberra headquarters - has never been busier, with the number of terrorist investigations rising from about 100 in 2005 to almost 300 this year.

But it is the far-right threat that may surprise the public.

As the recent case of Anders Breivik shows, the dangers posed by right-wing extremists have not abated, despite most intelligence agencies focusing on the threats posed by Islamic terrorism.

A Christian who described himself as a ''modern-day crusader'', Breivik killed 77 people during a bombing in Oslo and a shooting rampage at a teen camp at an island outside the Norwegian capital in July.

While the assessment does not suggest ASIO has uncovered right-extremists in Australia that mirror Breivik's murderous intentions, it reveals they rely on overseas connections and events to inform and motivate them.

''[They] maintain links and draw inspiration from like-minded overseas extremists, and much of their rhetoric and activity is derivative, heavily influenced by developments overseas,'' it states. Websites such as stormfront.org - the web's most famous and ubiquitous white supremacist and neo-Nazi website - have numerous Australian members.

However, the threat posed by Australian right-wing extremists seems to be limited, with such groups appearing to be interested only in ''propaganda and engendering support''.

''However, there is always the possibility of a lone actor or autonomous group inspired by a nationalist or racist extremist ideology engaging in violence as a means of provoking a wider response,'' the report says.

It states the continued existence of such groups has directly led to the resurgence of an ''anti-fascist'' movement.

''[The anti-fascist movement] aims to confront those it identifies as fascists, including some of the nationalist and racist extremist groups also of interest to ASIO,'' it states.

The security assessment also discusses its monitoring of ''issue-motivated groups'' - organisations ranging from community-based forestry groups to neo-Nazi parties.

''There is … a small minority who seek to use protests around a range of emotive issues to further their own (often unrelated) political agenda by provoking, inciting or engaging in violence. It is this fringe that is of concern to ASIO.''

The head of ASIO, Director-General of Security David Irvine, also suggests cuts to ASIO's budget since 2009 - after the huge rise since 2001, the agency lost about $30 million over the past two years - may affect its work. ''ASIO will not be able to rely on current levels of funding to sustain its ongoing activities,'' Mr Irvine writes.