The next prime minister will have to raise the consumption tax to pay for ballooning social security costs, Finance Minister Sadakazu Tanigaki said Sunday.
"I believe it is unavoidable, although I don't know whether or not I will become (the next prime minister)," Tanigaki said on a TV talk show.
The finance minister is considered a possible successor to Prime Minister Junichiro Koizumi, whose term as head of the ruling Liberal Democratic Party expires in 11 months.
Koizumi has reiterated his policy of keeping the consumption tax at its current level of 5 percent while he remains in office.
But Tanigaki said, "We must form a conclusion toward fiscal 2007 on reviewing the entire tax systems," indicating his belief that the consumption tax issue should be taken up in earnest.
The scale of the increase should be determined in the context of what levels are appropriate to fund social security, he said.