The Immigration Bureau's (IB) detention of Hakeem AlAraibi, a refugee footballer from Bahrain who lives in Australia, conforms to international law on human rights, says IB commissioner Surachate Hakparn.
Pol Lt Gen Surachate made the remark at his meeting on Monday with acting Australian ambassador to Thailand, Paul Stephens, according to the commissioner.
He said he had explained to the envoy that the bureau has strictly followed the law in detaining AlAraibi and that the refugee was being treated in accordance with international regulations.
Last week, rights activists demanded the release of AlAraibi who may be deported back home where they say he could face persecution.
Activists began tweeting on Monday that AlAraibi had been taken from the Suan Plu IDC (Immigration Detention Centre) to an unknown place.
University of Sydney tutor Zainab Abdul-Nabi said there were strong fears he was being prepared for deportation to Bahrain.
AlAraibi was arrested on arrival at a Bangkok airport earlier based on an Interpol notice issued at Bahrain's request.
AlAraibi was convicted of vandalising a police station in Bahrain and sentenced to 10 years in prison in absentia. He has denied wrongdoing.
Previously, Australia's Department of Foreign Affairs and Trade said in a statement it was "in direct contact with Thai authorities regarding this issue", but declined to elaborate.
AlAraibi has been a vocal critic of the president of the Asian Football Federation, Sheikh Salman Alkhalifa, who is a cousin of the king. He was tortured by Bahraini authorities because of his brother's political activities during the Arab Spring uprising in 2011, according to Human Rights Watch.
Thailand's Foreign Affairs Department said Thailand does not have an extradition treaty with Bahrain. However, a request could be considered on a case by case basis, according to the department.
AlAraibi was granted refugee status in Australia in 2017 and plays for a Melbourne club.