The issuance of Japanese government bonds (JGBs) could rise above 175 trillion yen in 2014/15 from 170.5 trillion yen in the current fiscal year through March 2014, with roll-over of maturing debt seen reaching around 120 trillion yen.
New debt issues, or bonds to finance a revenue shortfall in the fiscal year beginning in April 2014, are expected to be lower than the current fiscal year's total of 42.8 trillion yen ($436 billion).
Goldman Sachs analyst Masahiro Nishikawa estimates the
total debt issuance is likely to increase to around 175 trillion yen or more.
In addition to refinancing and fresh borrowing, the government also sells bonds for its loan programme and for reconstruction after the damage from tsunami in 2011.
Japan has committed to halving the ratio of its primary balance deficit to its gross domestic product by fiscal 2015 to 3.3 percent from 6.6 percent in 2010.
But government ministries' budget requests would be a record 99.2 trillion yen for the fiscal year from next April, sources familiar with the figures had told Reuters last week.
The government has set budget guidelines without its usual spending cap, given the uncertainty over tax revenue as it will decide by October whether the economy is strong enough to raise the sales tax next April as planned.