The prime minister has said Thais should be honoured that the Olympic torch was passing through their country on Saturday and protesters would be "crazy and unreasonable" to disrupt the relay.
The torch arrived by plane on Friday under tight security and was quickly whisked to a luxury hotel.
Thailand's crown princess welcomed the flame shortly after its arrival.
The police and military were ordered to secure the relay to prevent disruptions from protesters of China's human rights record.
Prime Minister Samak Sundaravej said his government was certain it could provide adequate security and lashed out at anyone who might try to disrupt the relay.
"Whoever tries to destroy the flame is crazy and unreasonable," he said. "Why would anyone protest in Thailand? Why don't they protest in China?"
Protests over China's suppression of Tibetan demonstrations have dogged the torch relay at various stops on its worldwide journey that began at the ancient site of the original Olympics in Greece.
"This is a good thing for Thailand," Samak said. "Thai people should be proud."
A coalition of human rights and other activist groups in Thailand said they would hold a peaceful protest outside the UN's Asian headquarters, which is along the planned relay route in Bangkok.
"We want to show the Chinese government that the crackdown in Tibet did not spark outrage only in the Western world," said Pokpong Lawansiri, coordinator of the Free Tibet Movement.