TOKYO, July 6 (Reuters) - Japan’s Nikkei ended modestly higher on Tuesday as shares of SoftBank Group and Fast Retailing rebounded, although worries over a potential spike in coronavirus infections during the Olympics limited gains. The Nikkei share average closed 0.16% higher at 28,643.21, giving up earlier gains of 0.5%. The broader Topix gained 0.28% at 1,954.50. Tech-startup investor SoftBank Group rose 1% and Uniqlo clothing chain operator Fast Retailing added 0.45%, while air-conditioner maker Daikin Industries rallied 2.6%, following sharp declines on Monday. The Nikkei had slid more than 0.6% in the previous session after a rise in COVID-19 cases in Tokyo over the weekend. “It looks like there is some buying back of shares after yesterday’s sell-off,” said Masahiro Ichikawa, chief market strategist at Sumitomo Mitsui DS Asset Management. “There will soon be a big influx of athletes and media from around the world for the Olympics, and investors worry there could be a spike in infections, which is capping any rise in Japanese stocks.” Japan’s government is likely to decide on Thursday to extend a state of quasi-emergency in Tokyo and three nearby prefectures beyond an original end-date of July 11. Industrial machinery manufacturer Hitachi Zozen was the biggest percentage gainer on the Nikkei, rising 4.2%, while the biggest percentage loser was packaging container maker Toyo Seikan Group Holdings, which suffered a 4.1% decline. Among sectors, air transport gained the most on the Topix, adding 2.8%. Oil and coal producers were next, up 1.8%, followed by miners, which rose 1.6%. Shippers fell the most, down 1%, with securities firms down 0.7%, followed by a 0.6% decline for pharma companies. Reporting by Kevin Buckland in Tokyo; Editing by Shailesh Kuber and Amy Caren Daniel Our Standards: The Thomson Reuters Trust Principles.