Government authorities have decided to get involved in the investigation of some alleged misgivings of the MTAA Superannuation Fund management that can result to millions of losses for Australians investing their hard-earned incomes.

No other than Assistant Treasurer Bill Shorten, who has pledged to form an investigation and the Productivity Commission leading the inquiry.

The investigation comes as more reports arose about MTAA's access to workers' contributions in spite the fund's poor performance. There were also alleged claims that MTAA is losing millions from its investments, related reports from the Australian and the AFR said.

Mr Shorten said the inquiry would be conducted by the Productivity Commission sometime next year, and a resolution would be reached during the current term of government, according to the AFR.

Reports that the MTAA Super Fund has acquired the services of the bank Macquarie Group to oversee sales of key infrastructure investments have also come into fore.

According to the Sydney Morning Herald, the MTAA Super, with estimated assets under management worth $5.8 billion, has begun its write-downs of investments in US port operator Carrix.

The SMH indicated that the lower valuation of competitor AustralianSuper prompted the trustee of the MTAA fund to cut its asset value for Carrix.