Another said: “We invented Israel when saving them from Hitler, who now seems to be their teacher.”
A third tweet read: “I will never forget and I will make sure my kids teach their children how evil Israel is!”
One post was used to ask why Islamic State forces were “not attacking the real oppressors, Israel?”.
Ms Kirby was suspended as a candidate by party officials on Saturday.
Another Labour candidate standing for a seat in Wales was reprimanded after posting a message which appeared to compare Conservative politicians to Nazis.
Labour's annual conference is getting under way in Manchester today. Leader Ed Miliband is due to speak at a Labour Friends of Israel fringe meeting on Tuesday evening.