Superannuation savers face double taxation of capital gains under Treasurer Jim Chalmers’ planned extra tax on super balances above $3 million, which is the Labor government’s major revenue-raising initiative for its second term.

Tax experts said that under the proposed law, wealthy superannuants would pay both the additional 15 per cent tax on the annual value of unrealised gains on assets inside a super fund, plus the existing 10 per cent discounted capital gains tax rate when the assets are sold. There will be no credit provided for the tax on unrealised gains when capital gains tax is paid after assets such as shares, property and businesses are sold.