Young Australians are being locked out of a "generational bargain" as the wealth gap between children and their parents soars, new figures show, as the government prepares the terms of reference for its landmark retirement income review.

The review, recommended by the banking royal commission, is likely to dominate the government's agenda next year as Treasurer Josh Frydenberg draft the terms of reference for the all-encompassing inquiry into pensions, superannuation, aged care funding, housing and the equity of taxpayer funding across generations.

Young Australians could be worse off than their parents. Credit:Shutterstock

In a report to be released on Monday, the Grattan Institute found Australian household wealth has tripled over the past 30 years from $2.8 trillion in 1990 to $10.3 trillion in 2018.

"But the wealth bonanza has been far from equally spread. Most of the increase in wealth has been accumulated by older households, who benefited most from the housing boom and growth in superannuation assets," researchers Danielle Wood and Kate Griffiths found.