Thai media reports preliminary dam construction has begun well before official clearance by the Mekong River Commission.
Human Rights Watch, Amnesty International and other major international groups have called on the government to drop the law entirely.
Critics say the law will erode development progress Cambodia has made over the past 20 years.
On Wednesday, 62 international NGOs working in Cambodia stated their strong opposition to the law.
According to the Ministry of Labor, Cambodia sent nearly 5,800 legal workers in Malaysia in 2010, nearly two-thirds of them women.
The statement comes as local groups say talks with the government over the law have yielded few changes to the draft.
The amendments to the law will give more power to the head of the Anti-Corruption Body, which has executive power.
Up to 1,500 families have had to leave the lake area to make way for a massive commercial and residential development.
Families say they were pushed from 352 hectares of land and forced to relocate to Preah Sihanouk province.
Cambodia has at least 62 unions that represent many of the nation’s 300,000 factory laborers.
The UN agency said nearly three in four children at orphanages have at least one parent.
The changes to the law come as officials work to bring it into full effect, including a declaration of assets by public servants.