TOKYO, May 16 (Reuters) - Japanese government bonds edged down slightly on Monday, with the 30-year zone still feeling the effects of lacklustre results at an auction last week.

The Bank of Japan refrained from purchases under its asset buying operations.

The benchmark 10-year JGB yield rose a half basis point to minus 0.110 percent, while the 10-year JGB futures contract ended nearly flat, up 0.02 point at 151.95 2JGBv1>.

The 5-year JGB yield also rose half basis point to minus 0.230 percent. On Tuesday, Japan's Ministry of Finance will auction 2.4 trillion yen ($22.07 billion)of 5-year JGBs.

The 30-year JGB yield added 1.5 basis points to 0.360 percent. A 30-year auction last week drew only tepid demand.

Japan's top government spokesman denied a weekend media report that Prime Minister Shinzo Abe has decided to delay a sales tax hike scheduled for next year.

Abe said on Monday a majority of Group of Seven leaders agree on the need to deploy fiscal stimulus measures to boost global demand.

Abe also said that if the BOJ had not launched its quantitative and qualitative easing programme, Japan would still be in deflation.

($1 = 108.7600 yen) (Reporting by Tokyo markets team; Editing by Shri Navaratnam)