The two-year jail sentence of a rights worker for Licadho will not deter the groups work, a senior Licadho monitor said Thursday.
The complaints encompass allegations of corruption within the police and courts and in illegal logging and land disputes.
Officials from Licadho and the EU confirmed the closed-door meeting on Friday but declined to elaborate.
The tribunal has experienced cash-flow problems this year, with some donors reluctant to fund the court.
Cambodian consulates already operate in Seattle, Wash., and Lowell, Mass.
The preliminary talks will set the stage for a general border committee meeting that was postponed last month.
The Cambodian government is facing more accusations it has cracked down on freedoms of expression and the media in the past years.