TOKYO, Dec 29 (Reuters) - Long-term Japanese government bond yields eased on Wednesday in thin trading ahead of the new year holidays, as the Nikkei weakened. The 10-year JGB yield and the 20-year yield fell 0.5 basis point each to 0.055% and 0.465% respectively. Benchmark 10-year JGB futures barely moved at 151.85, with a trading volume of 9,405 lots. The 30-year yield was flat at 0.680%. "Weakness in Japanese stocks is supporting the market, but at the same time, auctions of 10- and 30-year bonds next week are a weight," said Katsutoshi Inadome, senior bond strategist at Mitsubishi UFJ Morgan Stanley Securities. "But basically the market feels like it"s just drifting ahead of the new year." Benchmark two-year and five-year JGBs didn"t trade, and last yielded minus 0.100% and minus 0.085%, respectively.