Armed ethnic groups doubt that a nationwide cease-fire accord can be signed before elections in November.
A brutal attack on a former TV host by a powerful tycoon has sparked the event.
The rally will be held on Monday as parliament prepares to vote on the bill.
But Cambodia’s opposition says the government is in cahoots with Hanoi.
But with four months to prepare, voters express doubts that polls will be free and fair.
Authorities in Phnom Penh had rounded them up in June to clear the streets of “undesirables” in preparation for two public ceremonies.
The Cambodia National Rescue Party says the legislation contains many loopholes that would hurt NGOs.
Judge Mark Harmon had clashed with his Cambodian counterpart over authorities' failure to arrest criminal suspects.
Opponents say the legislation is discriminatory and not in line with human rights standards.
The map prepared by former colonial ruler France will confirm the accuracy of maps now in use, he says.
However, no MPs meet with the group to accept petitions.
The fighting comes as government representatives and armed ethnic groups continue to discuss a nationwide peace accord.
Myanmar's government 'not serious' about establishing democracy, one group says.
Many have become ill because of a lack of food, physical exhaustion and exposure to chemical odors.
An opposition lawmaker was barred from addressing the media.
Lawmakers continue to debate defeated amendment that would lead to power sharing among parties.
The move comes as the government prepares to publicly reveal the map it’s been using to determine the official border between the two countries.