The architect of the country’s higher education loans scheme says the Albanese government’s plan to slice $16 billion off existing debts is a political exercise and doesn’t fix emerging problems with the program, as economists warn Labor’s proposal will favour high-income earners.

Bruce Chapman, who designed the income-contingent student loan system known as HECS for the Hawke government in 1989, said he supported the other changes the government was making, including lifting the income threshold from $54,000 to $67,000 at which point loans must be repaid.