Indian Prime Minister Manmohan Singh has asked the Japanese parliament to support India's bid to join the club of civilian nuclear powers.
Singh will be seeking Japanese support for the nuclear deal with US
At the same time, he has reiterated India's "unshakable" commitment to nuclear non-proliferation.
India's nuclear deal with the US needs approval of the Nuclear Suppliers' Group, of which Japan is a member.
The two countries have come a long way since Tokyo imposed sanctions on Delhi following India's 1998 nuclear tests.
Mr Singh addressed the lower house of parliament and met the trade minister on the first of his four-day visit of Japan, the first by an Indian prime minister in five years.
He will meet Japanese Prime Minister, Shinzo Abe, on Friday.
Japan has been seeking warmer relations with India but has yet to offer a position on the India-US nuclear pact.
The controversial pact was signed last year to give India access to civilian nuclear technology even though it has not signed the Non-Proliferation Treaty on atomic weapons.
"Like Japan, India sees nuclear power as a viable and clean energy source to meet its growing energy requirements," Mr Singh was quoted by the AFP news agency as telling the Japanese parliament.
"We seek Japan's support in helping put in place innovative and forward looking approaches of the international community to make this possible."
In an aside from his prepared text, Mr Singh added: "At the same time, I would like to confirm that India's commitment to work for universal nuclear disarmament remains unshakable."
In a short speech to welcome Mr Singh, the speaker of the lower house, Yohei Kono, thanked the Indian parliament for its annual silent prayer for the victims of Hiroshima and Nagasaki.
He called on India to "mutually cooperate to abolish nuclear weapons".
Analysts say Japan's approval of the nuclear deal with the US would help Mr Singh.
Critics, including his Communist allies and the opposition Bharatiya Janata Party, argue he is too closely aligned with Washington.
Mr Singh also called upon Japan to help strengthen trade and investment ties between the two countries, saying they were "well below potential".
Japanese cars are household names in India
India is the largest recipient of Japanese development aid, but Japanese companies have focused on markets such as China, Thailand and Vietnam.
The Japanese trade minister, who met Mr Singh, pledged cooperation to create a mega "industrial corridor" including a high-speed train link between Indian capital Delhi and its financial hub, Mumbai (Bombay).