By Phil Mercer BBC, Sydney

Modern Australia is built on immigration. Almost a quarter of the population was born overseas. The number of settlers surged during the gold rushes of the 1850s but mass migration only began to boom after World War Two.

Tough policies are designed to deter refugees arriving by boat

"We have learned much about the importance of managing immigration to achieve very specific goals," said Australia's Immigration Minister Philip Ruddock. "The intake is critical to nation-building."

This goes to the heart of the government's attitude towards asylum seekers. It has insisted it will decide who is allowed to settle here and will not tolerate those it considers to be "queue-jumpers".

In Australia, there are two types of refugees: those who are resettled under official humanitarian programmes (600,000 since 1945) and those who arrive unofficially by boat, for example, seeking protection.

Tough policies on asylum are designed to deter the latter.

Anyone arriving without visas or passports and claiming refugee status is automatically locked away while their application is investigated.

I have no idea what will happen to me. I am in limbo. I fear they will send me back Sayed, asylum seeker

This policy of mandatory detention has been in place since 1992. The authorities insist it is necessary on health and security grounds. There are various routes of appeal if claims are rejected.

There is an expensive network of immigration camps. Some, like the multi-million dollar facility at Baxter in South Australia, are remote.

Others are in urban areas, such as Villawood in Sydney and Maribyrnong in Melbourne. Hunger strikes, riots and self-harm have been a feature of life behind the razor wire fences.

Uncertainty

Sayed Reza was held at a detention centre in Western Australia.

There is an expensive network of camps

Like many asylum seekers, the 30-year-old Afghan risked his life seeking sanctuary in Australia after escaping persecution at the hands of the Taleban, who had murdered his brother. He paid a gang of smugglers to take him by boat from Indonesia.

After 10 weeks in detention, Sayed was released on a three-year temporary protection visa (TPV), when his claim for political asylum was accepted.

"I will pray forever for Australia," he told BBC News Online. "I am so happy here. I want to finish my exams, finish university and one day work for the government."

Sayed's relief and gratitude is tempered by uncertainty.

Like other refugees, he doesn't know if his TPV will be extended, given the government now favours the repatriation of Afghan asylum seekers.

"I have no idea what will happen to me," said Sayed. "I am in limbo. I fear they will send me back."

'Extreme attitude'

Australia's policies on asylum have provoked passionate debate.

Ian Rintoul from the Refugee Action Coalition told the BBC the authorities' hardline approach had rubbed off on the wider community.

Some asylum seekers are sent to centres on remote islands, such as Nauru

"The government's policies have created an extreme attitude to asylum seekers and encouraged the worst kind of discrimination," he said.

Uncompromising talk on illegal immigration has been a vote-winner.

The conservative Prime Minister, John Howard, won a third term in November 2001 due largely to strict, new measures against boat people. Australia's maritime borders were effectively sealed.

Those attempting to enter by sea were either turned back or sent to offshore refugee centres on Manus Island in Papua New Guinea or on Nauru, the tiny South Pacific republic.

So would a change of government result in a fundamental shift in asylum policy?

Probably not, according to an editorial in the Sydney Morning Herald: "This is an area of deep and serious division in public opinion, that, however, is not reflected in a contest of ideas between the two main political parties," it said.

"Labor (the left-of-centre opposition) criticises at the margin, but it will not oppose the government's fundamental stance of showing ruthlessness in dealing with boat people."