Sam Rainsy told reporters Sunday he planned a larger demonstration soon.
The proposed March comes as workers face increasing pressure from food and fuel prices, while salaries remain low.
Ouk Seng said Thursday she had made up the allegations because she wanted to return home to her children.
A spike in food rising prices has been felt by Cambodians of many walks of life.
Japan has been one of Cambodia’s largest donors, giving nearly $2 billion in aid packages since 1992.
Thai media reports preliminary dam construction has begun well before official clearance by the Mekong River Commission.
Critics of the dam say it will hurt ecosystems in the river that provide a major source of fish for Cambodians.
Lowell has the second-largest population of Cambodians in the US, and will spend up to $700,000 when the project kicks off this summer.
Peter Brimble, a senior economist for the Bank, said growth in 2010 showed Cambodia on a strong footing.
According to the Ministry of Labor, Cambodia sent nearly 5,800 legal workers in Malaysia in 2010, nearly two-thirds of them women.
Some 42 families had contested his claim to the land, beginning in 2003, but lost their claim to a lower court in 2004.
Air France’s Flight 274 will fly three times per week with a stop in Bangkok.