Australia is known for its tough asylum laws

Initially there was confusion over whether the boat, the Hao Kiet, had actually managed to enter Australian waters before being detained by officials.

Would-be asylum-seekers detained outside the country's so-called migration zone cannot appeal their cases in Australian courts.

On Friday, however, Mr Ruddock conceded that the boat had not been intercepted in time, and therefore the Vietnamese on board would be entitled to have their claims for asylum processed.

"However, it would be pre-emptive to suggest that any of these people are asylum seekers," Mr Ruddock said.

"Once at the processing facility they will be interviewed to ascertain who they are, where they are from and why they have come to Australia."

The Vietnamese are currently en-route to a detention facility on Christmas Island, 1,800 km (1,100 miles) from the mainland, after being picked up by a navy frigate.

When they arrive there later on Friday, they are due to be questioned under Australia's tough immigration laws.

Christmas Island is deliberately outside the migration zone.

Asylum seekers who do not make it as far as Australian territory are often taken to camps there or on Nauru or Papua New Guinea, where they are not given legal assistance or the right to appeal immigration decisions, under changes to Australia's asylum policy decided in 2001.

'Major failure'

The Hao Kiet, a fishing boat, was carrying 27 men, 17 women and nine children.

It is believed to have sailed within a few kilometres of the coast before being spotted.

The migrants are the first asylum seekers to have made it so close to Australia for 18 months.

Immigration officials said they knew the boat was on its way from Indonesia, but somehow lost track of it.

Mr Ruddock has refused to blame the navy or the coastguard, saying it is often difficult to detect small boats in a "very large ocean".

But the country's failure to intercept the boat earlier has sparked criticism that the government is neglecting homeland defence in favour of high-profile foreign military operations.

Opposition politicians described the incident as a "major failure in coastal surveillance".

Labor leader Simon Crean also said it highlighted the need for a dedicated national coastguard.

Meanwhile, an Australian man of Vietnamese descent has been charged with people smuggling in relation to the incident.

The man, named as Van Hoa Nguyen, was found on the Hao Kiet and is due to appear in a Perth court on 18 July.