Four Australians who are facing life sentences in Hong Kong have told the ABC's 7.30 program they are relieved to have been granted bail, but say they face an uphill battle to convince the courts they were duped by online scammers into smuggling drugs.

Brain-damaged WA mine worker Kent Walsh, 49, Darwin warehouse worker James Clifford, 62, Melbourne woman Suong Thu Luu, 44, and 79-year-old Melbourne pensioner Joerg Ulitzka are among nine Westerners whose cases were first uncovered by 7.30 earlier this year.

The alleged drug smugglers, from the Netherlands, Germany, the United States, UK and Australia, were caught at Hong Kong Airport with nearly $40 million worth of the drug ice as they set off for Australia and New Zealand between April 2014 and March 2015.

All nine insist they were scammed by a West African crime syndicate which lures vulnerable and elderly people into taking all-expenses-paid trips to Hong Kong with promises of money, romance or adventure.

In an unprecedented about-face in the Hong Kong High Court last week, prosecutors agreed to bail for the nine co-accused, raising their hopes that they could soon be exonerated.

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Australians insist they were groomed by online scammers

Ulitzka said he hoped the court would believe that he was lonely and bored when he was first approached online by what he believed to be a Congolese family who needed help recovering their money.

"When you get older, you have nothing to do. Play golf or sit on the computer? And then I got all these emails and I said, 'OK, I'll investigate that'. I already got conned out of a lot of money by scammers, but this was different," he said.

The scammers, posing as desperate refugees, offered to pay for Ulitzka to fly to Hong Kong to collect a suitcase they claimed would contain a special chemical they needed to remove black marks from their cash.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 8 minutes 54 seconds 8 m Drug mule accused Australians get Hong Kong bail as lawyers raise questions of AFP

In June 2014, he was arrested at Hong Kong Airport with a suitcase containing more than two kilograms of ice.

"I was devastated. I've never done drugs. I don't even know what they look like," Ulitzka said.

Walsh was arrested with nearly three kilograms of ice hidden in his bags while boarding a flight to Australia in March.

He said he believes the scammers were able to take advantage of him because he suffered a severe brain injury in a car crash six years ago.

"My thinking is a bit clouded ... my sisters tell me all the time I'm not the same person as I was before," he said.

Walsh said he had email evidence to prove the syndicate lured him to Hong Kong by claiming a long lost uncle had left him a $2.3 million inheritance.

While there, he said they lavished him with gifts including several pairs of shoes, which were later found to contain the drugs.

Nine co-accused relieved to be granted bail

In granting them bail last week, Australian-born High Court judge Kevin Zervos said: "On the whole, they are persons of hitherto good character who may have either naively or unwittingly got involved in a very serious crime."

Joerg Ulitzka was arrested with a suitcase containing more than two kilograms of ice. ( ABC 7.30 )

According to information provided to the court by Hong Kong Customs, the nine were arrested based on intelligence from overseas authorities in a joint operation with the Australian Federal Police and US authorities.

The court also heard that one of the group, Clifford, was stopped by Australian Federal Police before he left Brisbane Airport for Hong Kong last November.

Clifford told 7.30 the AFP warned him not to carry bags for anyone.

"They said, 'Be careful, there's scammers out there and it's a very bad place'," he said.

"I didn't even think about risking my life about it because it was greed that kicked in then — and then anything that these officers told me didn't even register in my head."

Clifford said he is focused on staying out of jail and getting back to Australia.

"I'll do whatever I can, whenever I have to do it to stay out of jail and keep everyone else out," he said.

Melbourne woman Suong Thu Luu is one of four Australians facing life sentences. ( ABC 7.30 )

"I'm just hoping and praying that I'll get back to see my family. With Hong Kong laws, it's a good possibility we won't get back. And that frightens me."

Eva Scheerlinck from Australians Detained Abroad said it was heartening the co-accused had been granted bail, but they faced many challenges in proving their innocence.

"All we can hope is that the goodwill being shown by the Hong Kong court in this case will extend to the agencies that are involved in it, and the lawyers here in Australia can get the information and the evidence that they need to help these people quickly and get them out quickly," she said.

The cases gained momentum after one of the world's oldest and most well-connected drug mules, 83-year-old New York socialite Elizabeth Kummerfeld, had her drug smuggling charges dropped in Hong Kong in April.

Ms Kummerfeld, the widow of former New York deputy mayor and News America president Donald Kummerfeld, was jailed for a year after being caught at Hong Kong Airport en route to Australia with two kilograms of ice in the lining of a backpack.

Dozens of Australians targeted by drug syndicates

A 7.30 investigation earlier this year found scores of drug smugglers have been arrested in Australia and in countries where they face the death penalty after allegedly being lured by drug syndicates online.

Australian authorities are aware of 40 arrests in Australia and 55 elsewhere, mostly in China and South-East Asia, but they believe the figure is higher.

Victor Twartz was detained at Sydney Airport with 4.5 kilograms of cocaine in his luggage. ( ABC News: Thuy Ong )

In June, 7.30 revealed that disability pensioner John Warwick died in a Chinese prison hospital last year where he was detained on suspicion of smuggling drugs after being lured to the city of Guangzhou by online scammers.

Several Australians jailed for drug smuggling in China also claim to be the victims of scams, including former Adelaide jockey Anthony Bannister, intellectually disabled Brisbane man Ibrahim Jalloh, and Bengali Sherriff.

In August, 7.30 revealed the Australian Government and Department of Foreign Affairs and Trade had made a series of high-level representations to China this year, troubled by the evidence the Australians detained there were duped or coerced into smuggling drugs.

The AFP also warned Australians to be wary of online scams after the arrest of 91-year-old retired dentist Victor Twartz, who was detained at Sydney Airport in July with 4.5 kilograms of cocaine in his luggage.

Ms Scheerlinck said people needed to step in if they suspected a loved one was being scammed.

"If you know of someone who has been having an online relationship, and all of a sudden they're being offered free flights somewhere or a free holiday, just remember there's no such thing as a free lunch — or a free flight in this case — and that you need to be very aware of what the risks might be."