
UNHCR representative Ray-mond Hall met Kasit at the ministry to request cooperation regarding the boat people.
"The minister will give me a formal reply and I believe the reply will be positive," Hall told reporters after the meeting.
The group of 66 was part of the 78 rohingya who landed on the Ranong coast on Monday. They were tried in provincial court while the 12 who arrived in a weak physical state or were wounded were hospitalised.
Prime Minister Abhisit Vejjajiva ordered a delay in the deportation of the 78 rohingya and assigned forensic expert Pornthip Rojanasunand to check their health.
Kasit said the Internal Security Operations Command (Isoc) would consider details and set procedures for the UN's access to the boat people.
The plight of the stateless rohingya ethnic group was highlighted three weeks ago when the Thai Navy was accused of towing nearly 1,000 of them out to sea and abandoning them with little food and water.
The UN refugee agency earlier requested access to 126 rohingya who reportedly beached themselves on Thai shores early this month. But the group was reportedly escorted by the military out to sea last week.
The government denied the allegation of inhumane treatment but promised to look into the case.
The military-run Isoc has handled the investigation but the international community has doubts about its transparency. "The investigation will be very fast and we need to get transparency of the result to satisfy the broad number of stakeholders," Hall said.
Kasit defended Isoc, saying the law requires the agency to handle and investigate such cases.
"It is our internal arrangement. If the military investigation is not satisfactory, we can set up another group to do it," he told reporters. "Don't doubt before the investigation is completed."
Kasit said his government was seeking a regional approach to tackle the root cause of the problem.
Illegal migration was a complicated issue since smugglers and human traffickers were involved, he said. Thailand would raise the issue of the illegal migrants at many regional groupings including |Asean, Bimstec and the Indian Ocean Rim Association for Regional Cooperation, the minister said.