Japan's foreign minister said Tuesday he would visit Iran next month, in the latest sign of Tehran's rapidly thawing relationship with the Western world.

Fumio Kishida said he plans a three-day trip from November 9, the day after Iranian negotiators wrap up talks with world powers in Geneva over the country's nuclear programme.

Tokyo, which is heavily dependent on Middle Eastern oil, has maintained friendly relations with Tehran through its years of ostracism, keeping up a diplomatic two-way that many developed countries cut off decades ago.

Western nations, led by the United States, have long suspected that Iran is trying to build an atomic bomb but Tehran denies this, saying its nuclear programme is peaceful.

It has endured years of sanctions and defied multiple UN Security Council resolutions under hardline leaders.

But since President Hassan Rouhani, who is seen as a relative moderate, took office in August hopes have been raised of an end to the long-running crisis, especially after a round of hectic diplomacy during the UN General Assembly in September.

That set up a series of meetings, including one in Geneva next month of the so-called P5+1 -- the United States, Britain, France, China and Russia plus Germany -- with hopes high of a breakthrough.

Tokyo intends to play a role in asking Tehran to "show flexibility", taking advantage of its longstanding friendly ties with Iran, a foreign ministry official said, noting that Japan is one of a small number of wealthy countries that has an embassy there.

Even so, Japan reduced its oil imports from Iran last year by 40 percent in a nod to international sanctions.

Kishida's constituency is located in Hiroshima, one of two Japanese cities devastated by US atomic bombs towards the end of World War II. He "has strong interest in the nuclear issue", the official said.

The foreign minister is expected to head to India after Tehran.