An army of baby boomers, pensioners, and retirees could prove the unlikely salvation of Australia's anaemic retail sector after the over-65s age bracket emerged as the fastest growing segment of consumers shopping online.

Older people's sudden discovery of tablets and smartphones with which to do their shopping could help revive the fortunes of retailers, with many economists long concerned that the nation's ageing population would likely spend much less than a country skewed to a younger demographic, especially on discretionary goods.

Over-65s, who historically have made up the smallest proportion of online spending by age group, have raced ahead of their children and grandchildren to notch up the fastest growth in online shopping for the 12 months to April, the latest National Australia Bank Online Retail Sales Index has shown. For the three months to April, the pace of growth of online shopping by people aged over 65 was six times faster than the 35-44 age group.

''The fastest growing age category is now the over-65 group, who to date have really failed to embrace online to anywhere [near] the same extent as younger generations,'' NAB head of industry analysis Dean Pearson said.

Those in the 35 to 44 age group stalled in terms of online spending over the past year, with mortgage stress, job security worries and the cost of living blamed.