New analysis shows people who earn about $45,000 or $190,000 are penalised the most by bracket creep.
The federal opposition has promised to index income tax brackets and end bracket creep.
Economist Saul Eslake said he supported the idea in principle but was doubtful spending could be cut to offset it.
Workers who earn the minimum wage and those who are on the cusp of the top tax bracket are the hardest hit by bracket creep, according to new research.
The federal opposition wants to stamp out the longstanding feature of Australia's tax system, where people see larger proportions of their incomes taxed over time.
It occurs because tax brackets do not move with inflation, so people 'creep' into higher brackets.
Analysis by the e61 Institute and economist Richard Holden has found that workers earning about $45,000 and those earning about $190,000 are penalised the most by bracket creep, largely because their incomes are on the cusp of higher brackets.
Over a decade from 2028, someone who currently earns $45,000 would face an increase of more than five percentage points in their average tax rate. This level is close to the full-time minimum wage, although many part-timers also earn in this range.
Over the same period, someone who currently earns $190,000 would face an increase of more than four percentage…
