Prime Minister Binyamin Netnayahu mentioned the Geneva conference in his speech, lamenting the fact that "there are those who chose to participate in the display of hate."
Netanyahu directed a personal question at Swiss president Hans-Rudolf Merz, who earlier in the day defended his decision to meet Ahmadinejad in Geneva, prior to the opening of the conference.
"I turn to you, the Swiss president, and ask you: How can you meet someone who denies the Holocaust and wishes for a new holocaust to occur?"
Netanyahu praised "important countries" that chose to distance themselves from the conference, mentioning the United States, Canada, Germany, Italy, Poland, Australia and New Zealand.
Netanyahu called Ahmadinejad a Holocaust denier who wants to perpetrate another massacre of Jews.
"We will not allow the Holocaust deniers to carry out another Holocaust against the Jewish people. This is the supreme duty of the state of Israel. This is my supreme duty as prime minister of Israel," Netanyahu said.
"Israel," Netanyahu went on, is "the shield and the hope of the Jewish people. Here we create for the glory of our people and all of mankind. The country's achievements in every field - culture and science, medicine and security - are groundbreaking. We are a nation small in number but of great fortitude," Netanyahu said.
Netanyahu also hinted Israel had to be prepared to act alone against Iran if necessary.
Although he only mentioned the word Iran once, he devoted nearly all his speech to the Iranian threat. "Only a matter of a few decades after the Holocaust, new forces have arisen that openly declare their intention to wipe the Jewish state off the face of the earth," he said.
Netanyahu also discussed diplomacy he hoped would foil Iran's nuclear plans.
"We must appeal to the world's conscience and forge alliances," he said. "We must remember that our ability to fend off the dangers to our people's existence rests on the strength of our state, our cohesion and our unity at the moment of truth," he said. "The State of Israel is the shield and the hope of the Jewish people."
To the Holocaust survivors Netanyahu said: "The government has a deep commitment to you. In years past the state has not always known how to provide you with what you need, but things have changed over the last years. Today I promise you that we will continue to give the adequate response to your unique needs."
Watch the speech here
