The Thai government on Friday said they were "as lenient as possible" in their treatment of Burmese refugees living in camps in the kingdom, responding to US movie actress Angelina Jolie's call on authorities to allow the camp-dwellers more freedom.

On Wednesday Jolie, in her capacity as UNHCR Goodwill Ambassador, and her partner US actor Brad Pitt visited Karen refugees living in camps in Mai Nai Soi, in Mae Hong Son province, 600 kilometres north of Bangkok.

The camp houses 18,111 Karen refugees, many of whom have lived there for more than a decade fleeing fighting in their home state across the border in Myanmar.

"I was saddened to meet a 21-year-old woman who was born in a refugee camp, who has never even been out of the camp and is now raising her own child in a camp," Jolie said in a statement provided by the UNHCR.

"With no foreseeable chance that these refugees will soon be able to return to Burma (Myanmar), we must find some way to help them work and become self reliant," she said, appealing to Thai authorities to allow the refugees greater freedom in seeking work and getting education in Thai schools.

Thai Foreign Ministry spokesman Tharit Charungvat said they had not been officially informed of Jolie's request.

"We try to be as lenient as possible where we can, but we not a rich country and have our security to think of," Tharit said.

There are about 111,000 registered refugees living in nine camps in northern Thailand along the Thai-Myanmar border. They are not allowed to leave the camps to work.

Thailand has an estimated one million Myanmar nationals working as labourers in the country, many of them illegally.