The JVP trade union leader KD Lal Kantha said they had moved the Human Rights Commission (HRC) over the plight of the thousands of people displaced in Sampur due to the construction of the 500 MW coal power plant.
The work at the coal power plant, a joint venture between Sri Lanka and India's National Thermal Power Corporation, began in 2013, much behind the schedule.
Sampur was a key stronghold of LTTE in the east during their nearly three-decade-long military battle with the government troops.
Since the beginning of the construction work for the power plant, the displaced people have not been allowed to return to their original lands, the Eastern People's Voice movement said.
The Sampur coal power plant is regarded one of India's largest projects in post conflict Sri Lanka.
Founded in 1965, the Marxist JVP is also known as the People's Liberation Front.