If you lose your job past the age of 50, you are in the hardest age bracket to find work again thanks to age discrimination.

A recent study by the University of South Australia's Centre for Workplace Excellence confirmed there was a strong perception that older workers were not suitable for employment.

"Older job seekers that we spoke to felt they were rejected based on their age alone," the centre's Justine Irving told ABC Radio Adelaide's Drive program.

One-third of people surveyed aged over 50 revealed they had experienced age discrimination when applying for work.

"Feedback [candidates] were given about being overqualified or too experienced was interpreted as being just too old for the job," Dr Irving said.

"Some adults described a subtle pressure from their colleagues and management to stop working in order to make room for a younger generation."

Age-related discrimination was causing many to withhold their age on résumé, Dr Irving said.

The centre's study follows the Willing To Work Inquiry by the Human Rights Commission released in May 2016.

It revealed a rise in long-term mature-aged unemployment.

The report found the average length of time job seeking for those unemployed over 55 was 68 weeks.

Employment seekers aged 25 to 54 spent an average of 49 weeks looking for work, while it was a mere 30 weeks for 15 to 24-year-olds.

The report also found 27 per cent of people over 50 had experienced age discrimination.

Dr Irving said human resource managers needed to adapt and adjust to an ageing workforce or they would face large recruiting problems.

"It's important employers look for workers right for the job and not to make judgments about a person's capacity or abilities based on age alone."