The Laos government said Saturday it was "profoundly saddened" by the deaths of foreign tourists in Vang Vieng, with the toll from a suspected methanol poisoning incident now at six.

Two Danish citizens, an American, a Briton and two Australians have now died after being rushed to hospital following a night out in backpacker hot spot Vang Vieng.

They were among a group of about a dozen foreigners who fell ill and were rushed to hospital shortly after November 12.

In a statement on its website, Laos' Ministry of Foreign Affairs said Saturday it expressed "sincere sympathy and deepest condolences to the families of the deceased", adding an investigation was underway.

Australian Holly Bowles, 19, became the incident's latest fatality on Friday when she died in a Bangkok hospital surrounded by family.

Canberra is pressing Laotian authorities for a full and transparent investigation into what happened.

Vang Vieng has been a fixture on the Southeast Asia backpacker trail since Laos' secretive communist rulers opened the country to tourism decades ago.

The town was once synonymous with backpackers behaving badly at jungle parties but has since re-branded as an eco-tourism destination.

The Vietnamese manager of the Nana Backpackers Hostel where the tourists were staying has been detained for questioning, the Laos tourist police told AFP.

No charges have been filed thus far.

Police in Laos could not be reached for comment on Saturday.

Alcohol tainted with methanol, a toxic alcohol usually used in industrial and household products like antifreeze, is suspected to be the cause of the deaths.

It can be added to liquor to increase its potency but can cause blindness, liver damage and death.

Danish, Australian and British officials released statements confirming the deaths of their nationals in the week following the incident.

On their travel advice websites, UK and Australian authorities have warned their citizens to beware of methanol poisoning while consuming alcohol in Laos. 

But in Vang Vieng, business seemed to be going on as usual.

"I heard the news but everything is normal here," Michael, a manager at Vangvieng Rock Backpacker Rooftop Hostel told AFP on Friday, asking to use only one name.

"The high season is about to start, so we are welcoming more tourists every day." 

"There are still many tourists in town, and they go partying," a receptionist at Vang Vieng Chill House Hostel told AFP.