The two Prime Ministers had in 2015 welcomed the deal on the peaceful use of nuclear energy.
Ahead of Prime Minister Narendra Modi's visit to Japan for the annual bilateral summit, Japanese Ambassador to India Kenji Hiramatsu said today that the civilian nuclear deal between India and Japan will be done only after the technical details are finalised.
"We are now having technical discussions and the point is what we agreed upon last year was the agreement will be signed after the technical details are finalised," Hiramatsu said today.
"We are working around this line. We are in the process of technical discussions. With regard to signing, at this moment I cannot say it will be signed because we are in the process of technical discussions," he said.
"But I hope that some conclusion will be made during the Prime Minister's visit but I cannot tell at this moment it will happen or not, I hope you understand that," he said.
During Japanese Prime Minister Shinzo Abe's visit to India last year, New Delhi and Tokyo agreed to have a civil nuclear agreement once technical details were finalised.
A joint statement issued after the 2015 annual bilateral summit stated: "The two Prime Ministers welcomed the agreement reached between the two governments on the agreement between the Government of Japan and the Government of the Republic of India for cooperation in the peaceful uses of nuclear energy, and confirmed that this agreement will be signed after the technical details are finalised, including those related to the necessary internal procedures."
No date for completion of technical details was available.