As some of their number succumbed to methanol poisoning, other guests at the Laotian hostel at the centre of the probe tried to warn others to stay away - and the hostel reportedly deleted their warning.

Australia’s ABC is reporting that online reviewers desperately tried to get the word out before news of the first deaths were made public.

“Do not go here!! They have methanol in their drinks and me and three others have been hospitalised because of this,” one message shared by the ABC read.

“I stayed at this hostel for five days. Myself and friends were sick from consuming the free vodka here,” another tourist said.

“People we know were taken to hospital, some even in intensive care with serious problems. The ones in hospital have all had traces of methanol in their bloodstream which is incredibly dangerous.

“The only event that connects all the different people is drinking at this hostel.”

Six people have died and others have been violently ill after the suspected poisoning in Vang Vieng, popular backpacker town in the Southeast Asian country.

Methanol is sometimes added deliberately and illegally to alcohol and the owner of a hostel has been detained by police for questioning.

In response to the now-deleted reviews, the owners described the comments as a “slander case” and claimed to have “always prioritised the safety and wellbeing of our guests”.

Kiwi comes home

A Kiwi tourist believed to have been caught up in the poisoning returned home earlier this week.

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Australian teens Bianca Jones and Holly Bowles died in a suspected mass methanol poisoning event in Laos.

The Ministry of Foreign Affairs and Trade (MFAT) earlier said a New Zealand citizen was thought to be one of the poisoning victims.

On Monday, a spokeswoman confirmed the tourist had been able to return to New Zealand.

“The New Zealand Embassy in Bangkok [which has responsibility for Laos] has been providing assistance to one New Zealander who we believe to have been poisoned with methanol in Laos,” she said.

“They have now departed Laos and returned home.”

Mfat has updated its travel advisory for Laos to note there have been several cases of suspected methanol poisoning after consuming alcoholic drinks.

“Travellers are advised to be cautious about consuming alcoholic beverages, particularly cocktails and drinks made with spirits that may have been adulterated with harmful substances. Know the signs of methanol poisoning and seek immediate medical attention if poisoning is suspected.”

It’s understood the owner of the Nana Backpacker Hostel where the two friends had been staying was detained on Friday for questioning by police in Laos, according to the ABC.

The two Australian victims are believed to have started their night with free drinks at the hostel before heading out to other bars.

The ABC reports the hostel previously claimed the drinks in question did not come from its bar.

What does methanol poisoning do?

Victims can go into severe metabolic acidosis, when too much acid builds up in the body.

Symptoms include nausea, vomiting, and abdominal pain, as well as depression of the central nervous system. This can cause people to become unconscious and potentially enter a coma.

Methanol poisoning can also cause retinal damage, leading to vision loss.

Treatment includes supportive care such as intubation and ventilation to help the patient breathe, and some medicinal care may be provided to remove methanol from the body.

- Additional reporting, Melissa Nightingale