Activating The Genocide Convention
There are 149 states party to the Genocide Convention. Every one of them has the right to call out the genocide in progress in Gaza and report it to the United Nations.
In the event that another state party disputes the claim of genocide — and Israel, the United States and the United Kingdom are all states party — then the International Court of Justice is required to adjudicate on “the responsibility of a State for genocide.” Note that here “parties to the dispute” means the states disputing the facts of genocide, not the parties to the genocide/conflict. Any single state party is able to invoke the convention.