Amano is due to hold talks with French Foreign Minister Laurent Fabius who has come to Coburg hotel an hour earlier.
Russian Foreign Minister Sergei Lavrov is also on way to Vienna to join the negotiations.
Foreign ministers of the G5+1 and their deputies held a private meeting on Sunday afternoon to discuss the latest developments in the course of nuclear talks.
At the same time, Iranian foreign ministry deputies held a meeting with their US counterpart Wendy Sherman and are likely to meet with Deputy EU Foreign Policy chief Helga Schmid.
The sides hope to reach a deal before a July 13 deadline.
Iran and the six world powers have already missed three deadlines for achieving a final accord in this round of nuclear talks in the Austrian capital.
