The Lao government is "profoundly saddened" by the deaths of foreign tourists from drinking alcohol contaminated with methanol and pledged to prosecute those responsible.

Two Danes, two Australians, a Briton and an American have died after visiting Vang Vieng, an idyllic town that is popular with foreign backpackers, and drinking contaminated alcohol.

The government has been "conducting investigations to find causes of the incident and to bring the perpetrators to justice in accordance with the law," it said in its first official comments published on the foreign affairs ministry website on Saturday.

The government "expresses its sincere sympathy and deepest condolences to the families of the deceased," it said.

Lao state-run news agency KPL said on Friday that authorities were gathering evidence and witness accounts following the foreigners' deaths due to suspected "consumption of tainted alcoholic beverages".

Counterfeits of well-known alcohol brands and home-made spirits are a problem in Laos. Australia and Britain have warned their citizens to be cautious when consuming drinks there.

In response to the incident, the U.S. embassy in Laos issued a warning on Friday for its citizens to be on the alert for risks of methanol poisoning in consuming spirit-based drinks, advising them to buy from licensed vendors and check for signs of tampering or counterfeiting.

Methanol is a toxic alcohol that is used industrially as a solvent, pesticide, and alternative fuel source, according to the U.S. Centers for Disease Control and Prevention.