Young workers must change their saving habits or risk poverty in old age, according to the minister for pensions reform James Purnell.

Today's twenty and thirty-somethings are set to live longer than previous generations but if they do not change their saving habits they risk becoming a live fast, die poor generation he warned.

Some 3.7 million people aged between the age of 26 and 35 are currently either under-saving or not saving at all.

Government research revealed in the five years since 2000 the proportion of 20 to 29 year olds contributing to a private pension has fallen from one in three to one in four - figures for their parents' generation remained unchanged over the same period.

"At the moment young people are acting as if they expect to be able to fund a longer and longer retirement with less and less saving," said Mr Purnell.

"It is striking how fast time spent in retirement is lengthening. In 1950, the average retirement lasted about ten years. Today it's around twenty. In 2050, if we didn't increase the State Pension age, it would be around twenty-five years."

The government plans to tackle this problem through reform measures including auto-enrolment into a national pension saving scheme.