Treasurer Jim Chalmers has revealed the tax on offshore gas projects has raised more revenue than expected this year, as he prepares to hand down a budget focused on fixing a "broken" housing market and tax system.Mr Chalmers is widely expected to break an election promise and overhaul the 50 per cent capital gains tax (CGT) discount and negative gearing in Tuesday night's budget, which he admitted contained "a lot of political risk"."The status quo in the housing market and in the tax system is broken," he told the ABC."It's not working I do understand the arguments that people are making," he said."I did change the PRRT in our first term to get more revenue sooner."There will be a bit of an upgrade to PRRT revenue in the budget on Tuesday night."I know that people would like us to go further but there are good reasons to prioritise fuel supply and gas reservation."The PRRT raised $1.42 billion in 2024/25 and in December was forecast to generate $1.5 billion this financial year.Reflecting on One Nation's win in Saturday's Farrer by-election, Mr Chalmers said while his budget was not a "political document", it would respond to growing concerns held by disaffected voters."It will take into consideration and respond to what I think are very real concerns that people have about our economy and our society," he said."This government doesn't lightly dismiss or deny the very real concerns that people have, which are encouraging them to consider political alternatives."