TOKYO, Oct 6 (Reuters) - Japan's Nikkei reversed course on Wednesday to close at a more than six-week low, dragged down by concerns over higher interest rates, China's slowdown and modest approval ratings for the country's new prime minister.

The Nikkei share average fell 1.05% to close at 27,528.87, its lowest since Aug. 23. The index, which gained as much as 1.4% earlier in the session, closed in the red for a eighth straight sessions.

The broader Topix slipped 0.3% to 1,941.91.

"Japanese shares rebounded earlier in the session but the gains were not as strong as investors had expected, which drove them to start selling shares," said Seiichi Suzuki, chief equity market analyst at Tokai Tokyo Research Institute.

Heavyweights led declines, with Uniqlo clothing shop operator Fast Retailing losing 3.1%, chip making equipment maker Tokyo Electron down 2.08% and technology investor SoftBank Group falling 2.07%.

Local media poll showed Prime Minister Fumio Kishida is struggling to find his footing with voters just two days after he launched his new government. One daily showed his approval rating was at 45%, much lower than his predecessor Yoshihide Suga's administration when it came into power last year.

"That means Kishida's party will be unlikely to enjoy a land slide victory at the coming general election," said Kentaro Hayashi, senior strategist at Daiwa Securities.

Kishida's plans to raise capital gain tax could drive sell-offs as they want to lock in profits before the tax hike, Hayashi said.

Kishida, in his first news conference as prime minister, said this week tweaking the country's financial income tax rate will be among options in addressing income disparity.

Oil explorers and refiners advanced 3.8% and 3.1%, respecively, amid sky-high oil prices, while banks gained 2.84% on hopes higher rates would boost their profits. (Reporting by Junko Fujita; Editing by Krishna Chandra Eluri and Rashmi Aich)