CRA states that voluntary disclosure expenses are non-deductible

CRA has stated that "legal expenses incurred with respect to a voluntary disclosure are not incurred to earn income from a business or property."

This statement is too crisp.  Such expenses might potentially so qualify if, for example, they were incurred in relation to an HST voluntary disclosure, or with a view to satisfying conditions for a a business merger or the financing or re-financing of the business, or in order to remedy a default under current loans (although, depending on the circumstances, deductions might only be available under special rules such as the cumulative eligible capital rules.)

Neal Armstrong.  Summary of 5 June 2012 T.I. 2012-0437831E5 under s. 18(1)(a) - income-producing purpose and s. 60(o).