Islam Times reports from Al-Manar: "The Islamic republic's delegation headed by Dr. Ahmadinejad left for New York this morning to participate in the NPT review meeting," spokesman Ramin Mehmanparast was quoted as saying on state television's website.
"The president will take part in the conference to defend the rights of Iranian people and all nations," he said, adding Ahmadinejad will "frankly inform all about the Iranian nation's position."
Mehmanparast said Ahmadinejad will make a speech Monday when the NPT review conference begins.
Ahmadinejad is accompanied by Foreign Minister Manouchehr Mottaki, Iran's atomic chief Ali Akbar Salehi and other top officials.
Some 150 countries will meet in New York from Monday to review global efforts to check the spread of nuclear weapons.
The review conference, which is held every five years, comes 40 years after the landmark NPT came into force and it aims to discuss how to further the treaty's full implementation and universality.
Iran and many nonaligned nations argue that the NPT is discriminatory, dividing the world into an elite of nuclear haves lording over second-class nuclear have-nots.
The Iranians, backed by Arab countries, also want to turn the spotlight on Israel's sizable nuclear arsenal.
The focus in more than three weeks of discussions will be on the treaty's three main pillars: non-proliferation, disarmament and peaceful use of nuclear energy.
The NPT, the cornerstone of the global non-proliferation regime, is built on a grand bargain.
The five original nuclear weapon states -- Britain, China, France, Russia and the United States -- pledged to move towards disarmament. Non-weapon states forswore the bomb in return for access to peaceful nuclear energy.
But since the treaty came into force in 1970, Israel, India, Pakistan, and North Korea have all acquired a nuclear weapons capability. A total 190 countries have signed the treaty, including North Korea which however withdrew from it in 2003.
Israel, India and Pakistan have been invited at the conference, albeit without the right to speak, but none have said whether they will attend.
Israel is believed to have some 200 atom bombs but neither confirms nor denies this.
Tehran vehemently denies US charges that it is using his uranium enrichment program to mask a bid to acquire nuclear weapons. Iran’s Supreme Leader has renewed his ruling on acquiring nuclear weapons saying “it is against the teachings of Islam and it is forbidden.”