from 21st Century Wire:

There is no room to doubt that Israel’s bombing of Palestinian civilians and depriving them of food, water and other necessities of life are grounds to invoke the 1948 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.”