Industry superannuation fund Sunsuper has claimed the federal government's MySuper legislation contains unintended consequences based on the definitions and terms used in the draft legislation.

The current draft would make it difficult for super funds to convert default options into MySuper options, the fund said.

"There has been a view expressed at the superannuation industry level, which many superannuation funds will likely rely on, that funds will be able to convert their existing default investment options into a MySuper option, which will sit within their existing product offering alongside the other investment options," Sunsuper chief executive Tony Lally said.

"This is, however, not a view which is easily ascertained from the current drafting of the legislation.

"Our view and concern is that based on the current wording of the legislation, MySuper will have to be interpreted as a separate 'product' within a fund, separate to other 'products' in that fund."

The consequences of interpreting MySuper as a separate product are far-reaching, Lally said.

Members who are currently invested in both the default option (Mysuper) and in another investment option (choice) will need to hold two products and will be charged two sets of fees.

They are also expected to receive two annual statements and potentially hold two insurance offerings.

"This scenario applies to approximately 130,000 (over 10 per cent) of Sunsuper's members, and if these members were to hold two 'products' this would unintentionally and unnecessarily increase the number of superannuation accounts for members," Lally said.

Sunsuper made the comments in a submission to the Parliamentary Joint Committee on Corporations and Financial Services on the Superannuation Legislation Amendment (MySuper Core Provisions) Bill 2011, submitted earlier this month.