TOKYO: A Japanese filmmaker jailed for nearly four months in Myanmar described some of his detention there as "hell" and called on Tokyo to take a tougher stance against human rights abuses in the military-controlled country.

The Southeast Asian nation has been in chaos since the military overthrew an elected government last year. The junta has arrested thousands including politicians, students, journalists and foreigners as it attempts to smother dissent.

"It was horrible. I understood the concept of hell," Toru Kubota told reporters in Tokyo, describing conditions in a police lockup where he was first held after being detained at a protest in July.

He said he could barely lie down to sleep in the tiny crowded cell which was filthy and unsanitary and that he witnessed other detainees being beaten with batons.

He was later transferred to Myanmar's notorious colonial-era Insein jail where he was held in solitary confinement, he said.

A spokesperson for Myanmar's junta did not immediately respond to a request for comment.

Sentenced to 10 years for violating sedition and communications laws, Kubota was released in a mass amnesty this month alongside a former British ambassador and an Australian economic adviser to deposed leader Aung San Suu Kyi.

The economic adviser, Sean Turnell, also described filthy cells and having to eat out of a bucket while in a Myanmar jail in an interview with The Australian newspaper on Monday.

Vicky Bowman, Britain's ambassador from 2002-2006 who heads a group promoting ethical business in Myanmar, had been jailed for immigration violations.

Tokyo has cut aid to Myanmar and called on the military to stop the violence but its response has been more restrained than the strict sanctions imposed by the United States, European Union and others.

"I would hope the Japanese government would take a much stronger stance towards the Myanmar military," said Kubota, adding that any funds flowing from Japan to Myanmar should be closely scrutinised.

Japan's foreign ministry was not immediately able to comment.