TOKYO, Jan 4 (Reuters) - Yields on Japanese government bonds (JGBs) were little changed on Monday as traders awaited more details on a likely declaration of a partial state of emergency due to a spike in coronavirus infections. The government would consider declaring the emergency for Greater Tokyo metropolitan area, Prime Minister Yoshihide Suga said, adding that he will first consult with advisers before deciding on the details. A lack of clarity about the scale of the plan and whether the government will issue even more debt to subsidise businesses hurt by the outbreak kept many investors on the sidelines, dealers said. Suga also said he hopes to start coronavirus vaccinations by late-February, which could potentially reduce safe-harbour demand for government debt. Benchmark 10-year JGB futures fell 0.03 point to 151.89, with a trading volume of 15,416 lots. The 10-year JGB yield fell 0.5 basis point to 0.015%, and the 20-year JGB yield was flat at 0.395%. At the long end of the curve, the 30-year JGB yield was flat at 0.645%, but the 40-year JGB yield rose 0.5 basis point to 0.695%. The five-year yield was flat at minus 0.110%. At the short end, two-year JGB yield was unchanged at minus 0.125%. (Reporting by the Tokyo markets team; editing by Uttaresh.V)