The study, by the National Centre for Social and Economic Modelling at the University of Canberra and AMP, says it is ''bigger lifestyles'' rather than higher costs that are exerting pressures on many households.

''If there are pressures they are coming from keeping up with the Joneses and our higher expectations,'' Mr Phillips said. ''We're spending bigger, and on a wider range of goods and services, such as private schools, and we're spending more on discretionary or luxury items, like restaurants.''

The study shows income and pension gains and a decade of low inflation have meant all family types are relatively better off, including working families with children, pensioners, high-income earners, and even families in the lowest income quartile.

Working couples with children are $328 a week better off in real terms than in 2003, and single parents are better off - but only by $59 a week. The highest quintile of income earners are $576 a week better off.

The study, Prices These Days! The Cost of Living in Australia, says some necessities, including electricity, mortgages, medical services, fruit, bread and vegetables, have become more expensive but the price rises have been offset by dramatic falls in the cost of computers and audio/visual equipment. Items such as toys and household appliances have barely changed in price.