A man looks at St. Michael Cathedral standing near a monument to Princess Olga covered with sand bags to protect it from the Russian shelling, with placards displayed near the monument calling to support Ukraine, in central Kyiv, Ukraine, Monday, Dec. 12, 2022. AP
"The goal is now to build this platform quickly with the participation of Ukraine, international financial institutions and other partners," Scholz said after the leaders of the club of wealthy nations held online talks.
The meeting, which was also joined by Ukrainian President Volodymyr Zelensky, was held on the eve of the Paris summit which will look at what immediate assistance allies can give Ukraine over the winter.
Scholz said the reconstruction of Ukraine was "comparable perhaps with the Marshall Plan" -- which was put in place by the United States to help Europe rebuild after the devastation of World War II.
The G7 groups Britain, Canada, France, Germany -- which currently holds the club's presidency -- Italy, Japan and the United States.
Scholz did not give further details about the platform to support Ukraine.
But he said he was "convinced that it is our unity, our determination that has led to the Russian president standing all alone today.
"We call on (President Vladimir) Putin again to stop the senseless killing in Ukraine, and withdraw his troops."
The summit in Paris on Tuesday will see governments, business and aid agencies come together to discuss Ukraine's energy, health, food, transport and water sectors.
Ukraine's Prime Minister Denys Shmygal is to attend and Zelensky will appear via video link.
Zelensky tweeted on Sunday that he had spoken with French President Emmanuel Macron and US counterpart Joe Biden ahead of the G7 meeting and the Paris summit.
Biden reiterated Washington's strong support for the war-torn country and welcomed his counterpart's "openness to a just peace", the White House said.