Spokesman Sek Wannamethee said the Thai Embassy in Islamabad had not received confirmation about the students being released.
The five students were still in the custody of security officials at Lahore Airport and did not board flight TG346, which left the airport at 11.40pm on Friday and arrived in Thailand at 6.10am, as reported, he said.
Deputy government spokesman Sansern Kaewkamnerd also said the Thai Embassy had not received any confirmation about the release of the five or some of them, as reported in the media.
The Foreign Ministry is monitoring the situation and will correctly follow legal procedures, he said.
The public should exercise discretion in consuming news and not pressure officials of both countries regarding their work, as they have to follow the law, he said.
'No evidence of links to ISIS'
Reports that suggested the five had links to the Islamic State militant group of Iraq and Syria were groundless, he said.
"We have no evidence of any links between the students and any criminal organisation, so news that there is a link between ISIS and the students is not true," he said.
The men, who had been studying at a religious school in Pakistan, were trying to catch a Thai Airways plane at Lahore airport bound for Bangkok on Monday night when they were arrested.
A father has urged the government to help bring the five students back.
Suwan Songlong, 51, father of 18-year-old Sakkariya from Trang, said he was disappointed to learn that the report of four of the five Thai students being released was false.
He said he believed his son was innocent.