More than 500,000 members of the current workforce, almost half of whom are under 30, will be affected by Labor’s proposed superannuation tax when they retire if the $3 million threshold is not indexed to inflation.

The forecast, which is six times the 80,000 people the government says will be affected, was prepared by industry group the Financial Services Council. It predicts the overall number of affected workers would drop to 64,000 if the $3 million threshold was indexed as critics, including the Greens, are demanding.