While the recession has been characterised by rising under-employment - people doing part-time jobs but wanting full-time work or more hours in their current job - the TUC analysis of official statistics shows that too many hours is also a big issue, particularly for older women.
Around two in five women (40.1%) aged 50-64 say they want fewer hours in their current job. This rate falls for women aged 20-34, three in 10 (30.3%) who want less hours.
The fact that so many women are unable to work fewer hours in their current job shows that the widespread demand for more flexible work is not being met, says the TUC.
The report, which is released to mark the final day of the TUC Women's Conference in London found that too many people wanting fewer hours at work have to move into low-paid part-time jobs, rather than working fewer or more flexible hours with their current employer.
While nearly half of all women over 50 have part-time jobs, much of the work is very low paid. The majority of women over 50 in part-time work earn less than £10,000 a year, says the TUC.
TUC general secretary Frances O'Grady said: "While under-employment is a big issue for many workers today, there are millions of people that actually want fewer hours at work.
"The need to work fewer hours is particularly acute for the millions of women over 50 who have to balance work with multiple caring responsibilities.
"Unfortunately too many employers don't recognise any caring roles beyond motherhood, forcing many older women to trade down jobs in order to look after grandchildren, older kids or their own parents.
"As the population ages and people are expected to work for longer, the caring demands on women over 50 in work are only going to increase. Helping the two in five women over 50 who want fewer hours in their job is vital to meeting this demand.
"Providing more high quality flexible and part-time work will help more women over 50 to look after loved ones while continuing their careers. Employers would also benefit by holding on to talented and experienced staff."
She added: "The government can play its part too by providing stronger flexible working rights, particularly for those caring for parents and grandkids."
The report was based on a study of official employment statistics.
