TOKYO, Jan 7 (Reuters) - Japan's Nikkei average edged up 0.6 percent on Wednesday, buoyed by exporters such as Toyota Motor Co (7203.T: Quote, Profile, Research) on the yen's weakness against the dollar after the U.S. currency gained on hopes for a planned U.S. stimulus package. Regional banks are expected to be in focus after the Mainichi newspaper reported that the government had begun looking at injecting public funds into more than 40 regional banks. The benchmark Nikkei .N225 gained 33.82 points to 9,114.66, while the broader Topix .TOPX rose 0.5 percent to 880.35. (Reporting by Elaine Lies)