A Thailand governor has attacked New Zealand media for claiming a toxic insecticide caused the sudden death of a Kiwi tourist at a hotel in his province.
Sarah Carter, 23, became violently sick on February 3 while staying at the Downtown Inn in Chiang Mai and died a day later.
An elderly British couple, a Thai tourist guide and a Canadian man also died after staying at the Downtown Inn or using its facilities, while two other women died in similar circumstances within one month.
An investigation aired by TV3's 60 Minutes showed elements of the chemical chlorpyrifos, used to kill bed bugs, were found in the hotel room Ms Carter was staying in.
United Nations scientist Ron McDowall said the symptoms suffered by Ms Carter and the other tourists suggested they were killed by over exposure to the chemical.
But Chiang Mai Governor Panadda Disakul today told the Bangkok Post there was no medical evidence for that claim.
He criticised foreign media for "exaggerating" and said the incident had damaged Chiang Mai's reputation as a tourist destination.
Chiang Mai authorities would do all they could to uncover the truth about what killed the tourists, he said.
Earlier, authorities in northern Thailand ruled out the possibility of homicide or drug overdoses causing the mysterious deaths.
But the officials from the city of Chiang Mai told foreign consular officials on Thursday that investigations into the seven deaths are only halfway done.
Chiang Mai Public Health Office deputy chief Surasing Visaruthrat said they had found the chlorpyrifos theory "carries little weight", the Bangkok Post reported.
"We can't jump to a conclusion that toxin exposure was the cause of the death because the substance was allegedly found in the hotel room alone, not in the victim's body."
Dr Surasing said experts would meet again after receiving test results of samples collected from the victims' bodies, which were sent for testing at laboratories in the United States and Japan.
Meanwhile, the Ministry of Foreign Affairs and Trade (MFAT), on its safe travel website, said it was following up the unexplained deaths with the Thai authorities.
"The cause of death is unknown, and the results to date are inconclusive although there has been speculative media comment linking the deaths to local food markets and to the use of the pesticide chlorpyrifos in hotel accommodation," MFAT said.
It recommended travellers take general preventative health measures, including paying attention to personal hygiene, eating only hot food and drinking clean water.
Anyone who experienced severe sudden vomiting with or without diarrhoea should seek medical help immediately, it said.
"In light of the lack of any clear explanation of the recent deaths, it is up to individual travellers themselves to determine the risks of travelling there."