Three members of the World Wildlife Fund and Oxfam International were barred from future meetings for taking the Saudi plate at a June meeting, breaking it into pieces and distributing photographs of it in a toilet bowl.
Christiana Figueres, the top U.N. climate official, also said WWF and Oxfam will be restricted to sending two and three representatives respectively to the next round of talks in October. Normally, those groups might send a dozen or more activists.
Environmentalists have often accused the Saudis of obstructing the climate talks, which seek an agreement on limiting the world's emissions of greenhouse gases — mainly from fossil fuels — blamed for global warming.
The activists apparently felt provoked after the Saudi delegation tried to block a call for a study on what measures would be required to radically limit the expected increase in the Earth's temperatures this century.
Figueres said the unidentified WWF member who destroyed the nameplate was permanently banned from the climate talks and two others who played lesser roles were barred for the rest of this year.
WWF has said the chief offender has already been expelled from its ranks.
Saudi delegate Mohammad al Sabban said the two environmental groups "poison the atmosphere in which we are all working."
But he rescinded a call for a five-year suspension of the groups' participation at climate talks after leaders of Oxfam and WWF addressed a public apology to the delegates, who opened a five-day meeting on Monday.