By the BBC's Pam O'Toole

Australia has traditionally been generous when it comes to resettling people already recognised as refugees elsewhere.

But people arriving there illegally to claim asylum find themselves facing one of the toughest regimes in the world.

While their cases are being assessed they are automatically detained in one of six detention centres scattered across Australia.

Barbed wire

Woomera - the largest, with just under 1,000 inhabitants - is also perhaps the most remote.

Surrounded by barbed wire and several layers of fencing, it is situated in a former rocket testing range in the barren and dusty South Australian desert, almost 300 miles away from Adelaide.

In the summer temperatures can reach over 40 Celsius.

The centre was established on government land in 1999 to cope with a sudden influx of asylum seekers arriving illegally by boat.

The Australian police have used water canons to disperse rioters at the camp

As the number of such arrivals increased to around 5,000 per year, the original facilities were expanded and improved.

Portable buildings were brought in containing new, air-conditioned accommodation. Some play equipment was brought in for child detainees.

But Woomera remains a bleak place, with little for inmates to do.

When I visited there in March, the detainees - mostly Afghans - shuffled around aimlessly, or squatted under the canvas awnings provided.

Mostly Afghans

Afghans are by far the largest group in Australia's immigration detention centres, making up more than a quarter of the inhabitants.

Other major groups include Iraqis - around 13% of the centre's population - and Iranians at around 7%.

While most inmates have their cases processed in a matter of months, some can be incarcerated for several years.

Over the past 18 months there has been an increasing wave of discontent in these centres.

Woomera has suffered more incidents than most; Canberra says there have been eight fire-related incidents there in the past month.