Superannuation tax concessions for the wealthy would be wound back under a future Labor government as Bill Shorten seeks to position Labor as the party of fairness while also finding savings for a revenue-depleted budget.

Capitalising on public dissatisfaction at the extent of tax minimisation by wealthy individuals who have been able to park pre-tax income in superannuation accounts to avoid the top marginal tax brackets applicable to other earnings, Mr Shorten will announce the new policy formally on Wednesday.

The changes will limit the effective tax-free-threshold to superannuation earnings at or below $75,000 in any one year. After that amount is exceeded, a 15 per cent marginal rate would apply where currently there is none applicable. Labor estimates the size of the superannuation nest-egg needed to yield more than that in dividends would currently exceed $1.5 million.

A second change would reduce the high-income threshold at which the contributions to a super-fund attract a 30 per cent rate, twice the standard 15 per cent rate for everyone else.