The Australian government has updated its travel advice for Fiji to warn of methanol poisoning after four Australians were taken to hospital after drinking a cocktail at a well-known Fijian resort.
The four Australian women, aged between 18 and 56, are understood to be in critical condition in hospital on Monday morning after drinking the cocktail on Saturday afternoon at the Warwick Resort bar on Fiji's Coral Coast.
They were taken to the nearby Sigatoka Hospital with "nausea, vomiting and neurological symptoms".
Two of the group were taken to the Lautoka Hospital, north of Fiji's tourist hotspot of Nadi, on Sunday because of the severity of their conditions.
The ABC understands one, a 56-year-old Australian woman, has been under constant surveillance in hospital. Another, a 19-year-old woman, is also experiencing serious medical episodes from the suspected poisoning.
It is understood two other Australian women, a 49-year-old and an 18-year-old, are still critical but currently not as serious. But they were also transferred to Lautoka Hospital overnight to be monitored.
Guests staying at the resort have told the ABC the group was drinking pina colada cocktails by the pool on Saturday before falling ill.
The ABC has been told that some of the guests started having fits, chills and tremors on Saturday evening after drinking the cocktails.
The Australian government overnight updated its travel warning for advising tourists visiting Fiji to look for "potential risks" of "drink spiking and methanol poisoning" through consuming alcoholic drinks.
Fijian health authorities have started an investigation into the cause of the suspected poisoning and the ABC understands it has tested drinks from the resort.
However, it is not yet clear what actually caused the guests to fall ill. Fiji Police are also investigating the matter.
Warwick Resort told the ABC it was still operational.
"We don't have anything to disclose because the resort is under investigation," the resort's reception said.
The resort, a well-regarded stalwart of Fiji's tourism sector, describes itself as "perfect for family holidays, weddings or honeymoon".
"Our luxury resort in the Fijian Coral Coast sets the standard for exclusive beachfront resorts in Fiji," its website says.
The ABC understands on Sunday many guests were still unaware of the incident.
A Department of Foreign Affairs and Trade (DFAT) spokesperson said consular assistance was being provided to two Australian families in Fiji.
Three other people, understood to be two United States nationals and a Fijian, also fell ill after drinking at the bar on Saturday night.
They are still being monitored.
The travel warning from the Australian government comes just weeks after six people, including Australians Holly Bowles and Bianca Jones, died from suspected methanol poisoning in Laos.