"[Prime Minister Fumio Kishida] said that this time Japan has decided to provide an additional $1 billion in aid to Ukraine, including humanitarian and reconstruction assistance," the ministry said in a statement following the G7 online summit.
In total, Tokyo will provide Ukraine with $4.5 billion in assistance, including loan guarantees to the World Bank, according to the statement.
Last week, the World Bank said it would give Kiev a loan guaranteed by the Japanese government.
The G7 leaders held a virtual summit on Wednesday to wrap up Japan's presidency of the group. The G7 countries said in a joint statement that they were determined to continue supporting Ukraine.
The US and its allies increased their aid to Kiev shortly after Russia launched its special military operation in Ukraine. Moscow has repeatedly warned that foreign aid to the Kiev regime will only prolong the conflict.