Treasurer Jim Chalmers has been accused of trying to detonate a political landmine after flagging a plan to repeal a “widow’s tax” on investment properties — two months after concerns were first raised. Labor’s Budget sought to grandfather negative gearing and the 50 per cent capital gains tax discount for investment properties exchanged before May 12. Dr Chalmers on Tuesday night put forward draft legislation, with 17 days of consultation, to address the so-called “widow’s tax” — six weeks after the Senate passed the overall Budget package. Negative gearing for properties exchanged after Budget night would be restricted to brand new dwellings from July next year. The existing 50 per cent capital gains tax discount from that time would be replaced by a minimum 30 per cent tax on those future price gains.