Bank of Japan Gov. Masaru Hayami on Tuesday came out against a proposal that the central bank expand its buying of government bonds from the market, saying such a measure would be tantamount to underwriting newly issued bonds.

Hayami's remarks before the House of Representatives Finance Committee came a day after Chief Cabinet Secretary Hiromu Nonaka expressed strong expectations of the central bank's buying more government bonds to help stem the rise in long-term interest rates.

Under the proposal, which has been batted back-and-forth for a week now, the BOJ would absorb some of the excess supply of government bonds and keep them, in principle, until maturity.