Alan Fisher, Al Jazeera's correspondent in Geneva, said even though the declaration is being seen as a "significant diplomatic initiative", it could take years before the real effects are seen.
"It won't happen overnight and that has been the problem for this conference since it began in Durban in South Africa eight years ago," he said.
"They're trying to set up mechanisms so they can see how you put them into practice and how to monitor progress as well."
Ahmadinejad condemned Israel as a "cruel and repressive racist regime" in his speech to the conference on Monday.
It later emerged he had dropped language from his prepared speech, in which he described the Holocaust as "ambiguous and dubious".
The UN did not explain why the change was made, but Ahmadinejad's talk came after a meeting with Ban Ki-moon, the UN secretary-general.
Ban stressed that the UN did not equate Zionism with racism, and reaffirmed the historical facts of the Holocaust.
Many of those who remained to listen to Ahmadinejad's speech applauded his remarks but a number of Western nations, including the US, Britain and France, strongly criticised them.
The US, Canada, Israel, Australia, New Zealand, Germany, Poland and the Netherlands were among countries which had decided to stay away from the conference altogether amid fears Ahmadinejad would use the summit to propagate anti-Semitic views.
Silvan Shalom's, Israel's deputy prime minister, compared Iran to Nazi Germany in reaction to the speech, saying: "What Iran is trying to do right now is not far away at all from what Hitler did to the Jewish people just 65 years ago."
He made the remarks during a speech on Tuesday at the site of the Auschwitz-Birkenau Nazi death camp, hours before a Holocaust memorial ceremony.
Alan Dershowitz, a professor of law at Harvard University who attended the conference, described Ahmadinejad as an idelogical "successor to Adolf Hitler".
"I came face to face with evil yesterday. A man who would kill me if he could and kill my people and my children. A man who is a successor to Adolf Hitler ideologically but he will soon have nuclear weapons," he told Al Jazeera.
He said the conference in Geneva runs the risk of becoming a "hate-fest aginst the Jewish people".
"Ahmadinejad was the perfect speaker because he represented everything bad about this conference," Dershowitz said.
"I would hope that other democracies would understand this is not a place where democracy should be, this is a conference of tyranny."
Against this backdrop of renewed acrimony, China called for the international community to end its criticisms and focus on the conference's goals.
"We hope relevant parties can step up dialogue, eliminate disputes and concentrate on a consensus so as to combat racism with one voice," Jiang Yu, the country's foreign ministry spokeswoman, said on Tuesday.
Meanwhile, in Tehran, the Iranian capital, Ahmadinejad was met by a number of supporters as he returned after delivering his speech in Geneva.
Dozens of people gathered outside Mehrabad International airport to greet him, with some chanting "death to Israel" and "Zionist regime must be destroyed".
But not all Iranians have welcomed Ahmadinejad's comments.
Alireza Ronaghi, Al Jazeera's correspondent in Tehran, said the division between the country's conservatives and reformists was reflected in newspaper coverage of the president's speech.
"Ahmadinejad's speech seems to have had the same effect within Iran as it has abroad: antagonising his critics even further while forcing his supporters into a unified position, less than two months before Iran's next presidential election when Ahmadinejad himself will seek re-election," he said.