Nearly one in four jobseekers in Doncaster are aged 50 or over, new ONS data shows.
International Longevity Centre UK, a think tank, says older unemployed people are hampered by age discrimination and a lack of flexibility from employers.
In January, 6,670 people were out of work in Doncaster, of whom 1,480 were aged 50 or over – one of the lowest proportions of older jobseekers in the UK.
The data only includes people without a job who are claiming benefits linked to unemployment, either Job Seeker's Allowance or Universal Credit.
The bulk of unemployed people in the area were aged among 25 and 49 years old - 3,745 in total. Just 1,440 were between 16 and 24 years old.
Dr Brian Beach, a senior research fellow at ILC-UK, which specialises in researching the impact of longevity on society, said few older people benefit from effective support in their job search.
He said: "The key barriers older people face are ageist attitudes and a lack of flexibility in working arrangements.
"Tackling age discrimination must be the number one priority if we are to enable more people who want to work to find jobs in later life."
Across the UK, 27% of unemployed benefit claimants were aged 50 or older in January 2019 - 270,000 people.
A Department for Work and Pensions spokesperson said: "Experienced workers are a huge asset to the workforce and there are now 10.4 million over 50-s in employment – a record number.
"Through the National Careers Service and personal work coach support at their local Jobcentre Plus, we are supporting older people to get the work they want regardless of their age. "In addition, our Fuller Working Lives strategy is encouraging employers to recruit, re-train and retain older workers".
In Doncaster, the number of people claiming out-of-work benefits rose by 35% in the year to January 2019, compared with a national increase of 23%.
The ONS puts this rise down to the Universal Credit roll-out process.
A spokesman said: "Under Universal Credit, a broader span of claimants are required to look for work than under Jobseeker's Allowance. "As Universal Credit full service is rolled out in particular areas, the number of people recorded as being on the claimant count is therefore likely to rise."