Melbourne teens Bianca Jones and Holly Morton-Bowles, both aged 19, were among several tourists who were killed after drinking tainted shots at the Vang Vieng Nana Backpackers Hostel in 2024.
Two Danish women, an American man and a British woman also died in the incident.
Officials in Laos are expected to hold a press conference on Friday afternoon outlining the conclusion of their investigation into the incident, including charges laid on the suppliers of the tainted drinks.
Bianca's parents, Mark and Michelle Jones, told AAP they understand those allegedly responsible could be charged with two offences that collectively carry up to one year in jail, and a fine.
The charges that could be brought also include operating a business illegally.
"All up, our daughter, along with four other beautiful women, their lives are worth less than a year and about $1600," Mr Jones said on Friday.
"We're disgusted and angry.
"The whole way through this case, and ever since, our daughters and other girls were impacted by methanol, the Lao government has done next to nothing to secure evidence properly or to follow up."
Foreign Affairs Minister Penny Wong said the government felt ''deeply frustrated and bitterly disappointed'' that authorities in Laos are not pursuing the most serious charges in relation to the deaths.
''We have consistently made clear our expectations that charges should reflect the gravity of the tragedy,'' Ms Wong said in a statement, adding the government had advocated for a thorough and transparent investigation into the deaths.
''What happened to Holly, Bianca and four other foreign nationals should never have happened.''
Seasoned Australian diplomat Pablo Kang had been asked earlier this year to "explore all avenues to progress the case", and had engaged extensively with Lao authorities on behalf of the government and the families.
Mr Kang is expected to travel to Laos to convey the federal government's objections and reinforce the expectations for an investigation that delivers justice.
Ms Wong will speak with her Lao counterpart next week when she travels to Manila for the ASEAN-related Foreign Ministers' Meetings.
Both of Bianca's parents on Friday issued a warning to Australians to not to travel to the country.
"We've not come out before because we thought justice would be served but justice looks like it is absolutely not going to be served," Mr Jones added.
"Our very message to Australian and international travellers is do not go to Laos, it's a country that simply doesn't value life."
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