The parents of an Australian teen killed in a mass methanol poisoning in Laos have aired their fresh heartbreak as Lao officials prepare to finally lay charges on those allegedly responsible.

A Melbourne father whose daughter died from methanol poisoning in Laos has said he is "disgusted" over the charges expected to be laid.

DFAT has told the parents of the teens who died after a mass methanol poisoning incident that Lao authorities were unlikely to lay down severe charges.