Billions of dollars worth of federal government programs – including "pork barrel" spending on community centres, pools and sporting grounds – could be ruled unconstitutional in a High Court case to begin in Canberra on Tuesday.

The case has been launched by Toowoomba jazz singer and father-of-six Ron Williams, who won a 2012 High Court case challenging the legitimacy of the federal government’s school chaplaincy program. Legal experts say another victory for Mr Williams could throw up to 10 per cent of Commonwealth spending into doubt and reverse the trend towards centralised power in Canberra.

"This is a very big federalism case and will be important for years to come – it goes far beyond the school chaplaincy program," University of Sydney constitutional law professor Anne Twomey said.

"This goes to the Commonwealth’s ability to fund all sorts of programs where they don’t have the legislative power to do so."