TOKYO—Japan and Australia voiced “serious concerns” on Wednesday over reports of human rights abuses against Uyghur and other Muslim minorities in China’s far western region of Xinjiang, but Beijing dismissed the remarks as a malicious smear. Calls have grown from some Western nations to investigate if China’s actions in Xinjiang amount to genocide, as the United States and parliaments in nations such as Britain and Canada have described China’s policies there. “We share serious concerns about reported human rights abuses against Uyghur and other Muslim minorities in Xinjiang,” Japan and Australia said in a joint statement after a meeting of the defense and foreign ministers of both countries. “We call on China to grant urgent, meaningful, and unfettered access to Xinjiang for independent international observers, including the UN High Commissioner for Human Rights.” Japanese Foreign Minister Toshimitsu Motegi and Defense Minister Nobuo Kishi met their Australian counterparts, Marise Payne and …