The Laotian government has promised to bring perpetrators to justice after a mass poisoning that has killed six tourists including two Australians.

The death of Melbourne teenager Holly Bowles from a mass methanol poisoning incident in Laos has taken the death toll to six.She died after being on life support in a Bangkok hospital, a day after friend Bianca Jones died from consuming tainted drinks.

The father of Bianca Jones has issued a plea to the Laos government after she died from suspected methanol poisoning following a night out.