Auditors raised concerns around the solvency of a $124 million fund used by fugitive businessman Michael Gu to house money for a federal government visa scheme, calling into question oversight of the program designed to attract entrepreneurial migrants to Australia.

The Significant Investor Visa was one of the main fundraising mechanisms for the 32-year-old Mr Gu, who fled Australia on July 26 owing creditors of his collapsed iProsperity Group $350 million.