Former prime minister Tony Abbott has delivered a blunt warning that the May budget should not raise taxes, while the Turnbull government works on a housing affordability package to form the centrepiece of the budget.

But the housing package almost certainly will not contain changes to capital gains tax concessions after the government publicly ruled them out on Thursday.

Labor, which took a plan to reduce negative gearing and capital gains tax concessions to the last election, seized on a Fairfax Media report that the Coalition could curb CGT concessions for property investors to assist housing affordability and delivered a sustained attack on the Turnbull government in question time.

Options under consideration are said to include reducing the 50 per cent discount on CGT to 25 per cent; Grattan Institute economist John Daley said that change would eventually raise about $2 billion a year.