Firms are being urged not to "write off" older workers because of their age amid calls from the Government for people to seek a new career if they do not feel fulfilled in their job.
A new strategy was announced aimed at increasing the number of older workers as estimates showed that by the mid-2030s, over-50s will make up more than half the adult population.
Ministers and business leaders set out the social and health benefits of working longer, or switching to a new career later in life.
Work and Pensions Secretary Damian Green said: "Most people are healthier for longer and so are able to extend their careers and take up new opportunities.
"Staying in work for a few more years can make a significant difference not only to someone's income but also their physical and mental health.
"I urge all businesses to reassess the value of older workers. Nobody should write off hiring someone due to their age and it's unacceptable that some older people are overlooked for roles they would suit completely."
The Government said it will publish evidence to outline the benefits of working longer and will help people with health conditions and disabilities find a job.
A study published by ministers said: "The majority of British workplaces do employ at least some older workers. But although the number of older individuals in employment is rising, employment rates still drop sizeably when people reach their 50s and 60s.
"Existing legislation has already sought to encourage participation and retention of older individuals in the labour market, and to address age-related discrimination.
"While there has been an increase in the prevalence of formal equal opportunities policies explicitly mentioning age, far fewer workplaces have age-related equal opportunities practices in place.
"Findings from qualitative research commissioned alongside this study suggest some employers are wary of monitoring by age in case this is seen as discriminatory. This may be an area in which employers need reassurance."
The report said improving the experiences of older workers is important if they are to be encouraged to remain in employment longer.
Paul Green, of Saga, said: "An age-diverse workforce is a big win for individuals, businesses and for Government.
"The Government could also help by abolishing its tax on jobs - Employers National Insurance - for those who have been out of work for six months or longer, as long-term unemployment is a huge issue for those losing their job in later life.
"For many people, being able to continue to work is important, not just for the money but because it also boosts your physical and mental well-being."