Helping more older people into work should be at the heart of the Government's plans for full employment, according to a new report.
The Resolution Foundation said there was potential to increase employment among 50-to-64-year-olds by around 920,000 in the coming years, and by 240,000 for those aged between 65 and 69.
The think-tank said too many people were forced to leave the labour market prematurely because they they are ill or have caring responsibilities.
Workers who become ill, or take a break to look after a relative, should have the right to return to a job, it was argued.
This would help firms keep in touch with their staff and reduce the risk of people leaving the world of work, said the report.
Laura Gardiner, senior policy analyst at the Resolution Foundation, said: "Rising employment among older workers has been one of Britain's biggest labour market successes of recent years.
"This jobs phenomenon has been driven by a number of factors, including the rising state pension age, abolition of the default retirement age and better flexible working practices.
"But we can do far more to boost employment among older workers, in particular by helping them to stay in work when they take on caring responsibilities or have to adjust to ill-health.
"Many employers already see the benefits of holding on to these experienced members of staff but this attitude needs to spread throughout the labour market. Government policy interventions, such as an extension of rights to return to work, can help foster this change in attitudes towards older workers.
"Providing such support could help over a million older workers into jobs, and set the Government on course to meet its ambitious full employment target."
Lisa Harris, head of communications at Saga commented: "For many over 50s the opportunity to work for longer is welcomed as they genuinely don't feel ready to take that cliff edge decision to finish work completely.
"However we need to be mindful that for many the decision to reduce their working hours, or stop work altogether, is one that is well and truly taken out of their hands.
"With significant reductions in social care budgets, many older people are finding themselves in a position where they have to forgo their work-life balance in order to provide much needed care to loved a one."
Minister for Pensions, Baroness Ros Altmann, said: "For years I have championed the value of businesses hiring older workers and it's excellent that the number of them in employment, including older women, is now at a record high.
"It's clear employers are changing their attitude to older workers and taking advantage of the excellent skills and experience that they can bring to the workplace.
"Encouraging employers to adopt flexible working practices and provide support to older workers is essential if we are to see the employment rate for this group continue to grow."