Winthai said the authorities tried to enforce the law fairly.
He also chastised certain international organisations for spreading “inaccurate information” about the case.
An illegal public gathering carried a penalty of a fine or a few months’ imprisonment, he said, not “a long period of incarceration” as had been claimed by some organisations.
Nirun Pantarakit, a member of the National Reform Council, said the pressure from the international organisations would not have a serious impact on Thailand.
“This is an internal affair,” he said.
Worachai Hema of the Pheu Thai Party yesterday called for the immediate release of the anti-coup students.
He warned that public discontent would reach boiling point in a few months.