The legislation would punish people who refuse to acknowledge crimes, who deny or challenge the existence of crimes, or people who promote crimes committed under the ultra-Maoist Khmer Rouge regime.
People convicted under the law could be imprisoned for up to two years, or pay fines of up to 4 million riel (1,000 dollars).
Human rights groups have criticized the law, saying that it was drafted too rapidly. The Cambodian Centre for Human Rights (CCHR) said the timing of the debate in parliament, less than eight weeks before national elections, "suggests that it is politically motivated."
“[CCHR] believes that the Denial Law is unnecessary and [is] contrary to provisions protecting freedom of expression,” it said.
However Cheam Yeap, a lawmaker from the ruling Cambodia People Party said the law was not intended to punish people who simply want to talk about the Khmer Rouge regime.
On Wednesday, the National Assembly permanent committee stripped 28 opposition lawmakers from the Sam Rainsy Party and Human Rights Party of their parliamentary status and salaries.
Independent political analyst Kem Ley said this decision may affect the legitimacy of the law in the eyes of the people.
“[The] population and all stakeholders should be involved in the discussion of this law,” he said. “The draft was not carefully developed and remains without clear purpose and framework. However, I think such a law is important for Cambodia.”