A panel of experts advising Kishida this month recommended broad tax measures to pay for the hike and cautioned against raising debt that could expose U.S. ally Japan to international market changes.
Kishida's administration has pledged to "substantially" increase defense spending to counter what Tokyo sees as a growing security threat posed by China.
"Given the present security situation, we need to strengthen defense spending urgently in five years," Defense Minister Yasukazu Hamada told reporters after a meeting with the premier and Finance Minister Shunichi Suzuki.
"... He told us to make every effort in securing necessary (funding) quickly and firmly," he said.
To meet the size of Japan's mid-term defense plan, to be drawn up by the year-end, the government will decide on securing funding from both revenue and spending reforms.
"As a responsible nation, we must make the utmost efforts in spending reform, but at the same time steady funding sources are indispensable in order to stably support them," Hamada quoted Kishida as saying.