A letter addressed to Northern Ireland Secretary Chris Bryant calls for an international mediator to help resolve the long-running Drumcree march dispute.
Rights groups accused the UN of hosting a "war criminal" as some delegations walked out during the Israeli prime minister's speech.
The actors were among demonstrators detained by police at a Jewish Voice for Peace protest as Israel's prime minister addressed the UN General Assembly.
The actresses were arrested along with roughly 100 other protesters outside the United Nations ahead of the Israeli prime minister's General Assembly speech, Al Jazeera reported.