The benchmark 10-year JGB yield rose half a basis point to 0.145 percent, putting further distance between a record low of minus 0.210 percent last week. The 20-year yield also rose half a basis point, to 0.195 percent.
Government bonds like JGBs, German bunds and US Treasuries rallied earlier this month as Brexit worries gripped global markets. But they have recently come down from their highs as polls showed increased support for Britain remaining in the European Union.
Tokyo's Nikkei extended Monday's rally to rise 1.3 percent, adding pressure to JGBs.