TOKYO, June 2 (Reuters) - Japanese government bonds were steady to slightly weaker on Wednesday, with yields on long-dated bonds up slightly on the back of strength in domestic stock markets. The 20-year JGB yield rose 1 basis point to 0.455%, its highest level in nearly three weeks. The 30-year JGB yield rose 1 basis point to 0.690%, a high last seen in early April. But shorter maturities were flat with the 10-year yield unchanged at 0.075%, a day after there was no trade in benchmark 10-year bonds for the first time in almost a year. Benchmark 10-year JGB futures fell 0.01 point to 151.47, in thin trading volume of 14,823 lots. (Reporting by Tokyo Markets Team; Editing by Kim Coghill) Our Standards: The Thomson Reuters Trust Principles.