The costs are low and with people willing to pay large sums to move across borders the profits are very, very high.

Friendly face: Website welcomes legal immigrants

It is an issue that has been filling newspaper column inches and radio airtime in the United States, Canada, Australia and New Zealand as more and more vessels carrying dozens of Chinese migrants are found heading across the Pacific.

In Canada, public concern has been growing that more and more criminal gangs are targeting the country's west coast following a string of high-profile arrests both at sea and on land.

According to official government figures, at least 8,000 people illegally entered Canada in 1998 in an annual trade worth anything between US $120m and $400m.

That problem took centre stage once more in July this year when Canadian authorities seized a vessel off the coast of Vancouver Island and discovered more than 100 immigrants on board.

The crew told the authorities that the human cargo had been at sea for 39 days, with passage costing about $38,000 a head.

While there was enough rice on board the vessel, the water supply had been contaminated.

Last year alone, 1,365 Chinese immigrants were arrested as they tried to reach Canada's shores in similar circumstances.

At least one vessel containing an unknown number of illegal immigrants is believed to have sunk off the Queen Charlotte Islands.

And while officials have pledged to deal with the illegal immigration, campaigners have warned that Beijing will not allow migrants to return, leaving them in an international legal limbo.

'Snakeheads'

International governments have appealed to Beijing to stem the flow, saying that there is clear evidence that organised crime groups linked to the triads, China's mafia, are running human smuggling operations.

Speaking to the BBC, Mark Getchell of the International Organization for Migration, said that gangs known as 'snakeheads' were operating the vessels.

These criminals charged their cargo tens of thousands of US dollars for the trip, he said.

"The one thing about the smugglers is that they are flexible," said Mr Getchell.

"There is not one established route. When this one comes a little more difficult, they will find another one.

Mark Getchell: "The lure is an education and a future"

"What we have seen is that when there is a success and the passengers do get off-loaded and put in an asylum procedure, other boats follow suit. "It's organised crime," he said.

"These 'snakeheads' are taking advantage of people looking for a better life - and they have enough customers to pay these exorbitant fees. The ones I have spoken to have paid anything between US $25,000 and $40,000."

Many of the migrants are stowed deep inside cargo ships while others are taken to the US pacific territory of Guam, where they attempt to apply for asylum to the mainland.

Canadian authorities say that those who attempt the journey all the way across the Pacific do so in appalling circumstances, squashed into rusting vessels with inadequate food and water for a journey that can take more than a month.

If they survive that, and make it ashore, many find that they are not yet free.

"Many of them have made a down payment and when they reach their destination they have a debt to pay off," said Mr Getchell. "Women can get put in brothels or perhaps in some sort of sweatshop labour.

"But the lure for many of the younger boys that I have spoken to was an education, future and opportunity."

Legal barriers

Canada accepts about 200,000 legal immigrants a year but has been tightening its regulations on illegal immigrants and refugees.

Rocky ride: Migrants risk their lives to cross Pacific

While Canada's refugee authority now rejects around half of its 25,000 annual cases, one US immigration official has suggested that more migrants are heading for Canada as a result of the US tightening its own borders.

Despite this, Canada's recently appointed immigration minister, Elinor Caplan, has moved to dispel fears of a flood of illegal immigrants heading across the Pacific.

The government says that the Chinese community makes a great contribution to the Canadian economy and national life even if some of the refugees did enter illegally.

"Some have suggested that we should use force to keep these boats from entering Canada," said Ms Caplan.

"But the well-being of people who choose such a dangerous way to come to Canada is also a concern.

"Smuggling rings operate in a world beyond our borders.