Australia's government on Wednesday called on China to allow an Australian child and his Uighur mother to leave the country, days after co-signing a letter denouncing Beijing's treatment of the Muslim minority. China has rounded up an estimated one million Uighurs and other mostly Muslim Turkic-speaking minorities into re-education camps in tightly controlled Xinjiang region, in the country's northwest. Sadam Abdusalam has campaigned for months for his Uighur wife, Nadila Wumaier, and their son Lutifeier, whom he has never met, to be allowed to come to Australia.