When measured along income lines, men aged 25 to 44 and earning a high income were the most likely to be lonely.

When measured along income lines, men aged 25 to 44 and earning a high income were the most likely to be lonely. Photo: Quentin Jones

''ALL the lonely people, where do they all come from?''

In Australia, the answer to this plaintive question from the Beatles' Eleanor Rigby appears to be: from houses where men live alone.

One in three Australians experienced loneliness in the past decade, and younger people are more lonely when they have children, according to research to be released today by the Australia Institute.

Men who live on their own are at the greatest risk of loneliness but women are more likely to be lonely if they live in a couple relationship with children.

The study used federal government data from a survey of almost 20,000 people in almost 7700 households, as well as an online survey of almost 1400 people last June.

The institute's director of research, David Baker, found that the highest rate of loneliness of young adults, aged 25 to 44, was when they were living as a couple with children.

The research found that men living with a partner were least likely to be lonely - until they began having children. There was little difference in how women who lived in a couple or alone experienced loneliness.

When measured along income lines, men aged 25 to 44 and earning a high income were the most likely to be lonely, and women in the same age bracket but on low incomes were ''disproportionately more likely'' to be lonely.

The lonely had fewer friends on social networking websites such as Facebook, and were less likely to consider their online friends as real friends.

Mr Baker warned that despite the increase in use of sites such as Facebook, there was ''a risk that social networking sites may be overpromoted, especially to younger people''.