Kishida said the Japanese government would use 360 billion yen ($3.1 billion) in emergency funds to "minimise the negative impact on people's lives and corporate activity" caused by higher energy prices.
Details of the package will be announced on Friday, he told reporters.
They will likely include subsidies to mitigate the impact of "drastic changes in fuel prices" as the assault on Ukraine intensifies, Kishida said.
Japan has acted with its G7 partners to pressure Moscow over the invasion, and on Thursday Kishida said his country would freeze the assets of four Russian banks on top of three already sanctioned.
He also said virus measures imposed in parts of Japan, which mainly request venues to curb evening opening hours, would be extended for two weeks from Sunday in several areas including Tokyo.
Kishida will join a virtual summit later on Thursday with leaders of the United States, India and Australia, who are together known as the Quad.
