Labor will continue to pursue curbs on negative gearing and the capital gains tax discount on investment properties, despite questions over its effectiveness to help first homebuyers after a Treasury analysis found it would have only a small impact on house prices.

The Opposition has seized on secret 18 page analysis, released to the ABC after a two-year Freedom of Information fight, to claim vindication and accuse the government of over-egging its warnings about the supposed threat its policies posed for the property market.