Several Australians are seriously ill in hospital in Fiji with what local authorities suspect is alcohol poisoning.

The Department of Foreign Affairs and Trade (Dfat) confirmed through a spokesperson on Sunday evening that it was providing consular assistance to two Australian families in Fiji but declined to provide further details.

Seven foreigners including four Australians and an American were hospitalised after drinking cocktails at a five-star Coral Coast hotel resort, local health officials said on Sunday.

The hotel guests were taken to hospital on Saturday night suffering “nausea, vomiting and neurological symptoms”, Fiji’s health ministry said in a statement.

They fell ill after drinking a cocktail prepared at a bar in the resort about 60km west of the capital Suva, it said.

A ministry spokesperson said the guests, aged from 18 to 56, included four Australians, one American and two foreigners who lived in Fiji but whose nationalities were not given. All seven were initially taken to the nearby Sigatoka hospital.

Due to the severity of their conditions, they were later transferred to the larger Lautoka hospital on the island’s west coast, the ministry said.

Fiji police were investigating the incident.

On Sunday afternoon, Dfat updated its travel advice for Fiji to highlight a warning about the risk of alcohol poisoning.

“Be alert to the potential risks around drink spiking and methanol poisoning through consuming alcoholic drinks,” the updated advice stated. “Get urgent medical help if you suspect drink spiking.”

Guardian Australia understands the consular support being offered to the Australian families may involve assisting with hospital visits and liaising with local authorities.

The suspected alcohol poisoning incident comes after two 19-year-old Victorian women, Bianca Jones and Holly Bowles, died from methanol poisoning in November after drinking tainted alcohol while holidaying in Vang Vieng in Laos.

– Additional reporting AFP