Are price increases impacting disproportionately on some households?

The St Vincent de Paul Society has released The Relative Price Index which assesses the impact of the CPI on various household groups and the implications of changing cost pressures for some households. 

 The report concludes that CPI is not necessarily an accurate cost-of-living indicator. The price index can significantly underestimate the true increase in the price of goods that some household groups typically consume.  It also significantly understates the contemporary cost pressures on these household groups.