The ONS said the rise is partly due to more people staying on in work and also more people of this age group in the population.
Both the number of people in work and the employment rate for those aged over 65 is the highest since records began.
From February to April 2013, the employment rate for over-65s was 9.5%, the ONS said.
Jim Hillage, director of research at the Institute for Employment Studies, said: "While these figures reflect a willingness among employers to recruit and retain experienced people, it may also reflect the need that some older people have to top up inadequate pension arrangements."
The charity Age UK welcomed the news, saying the figures represent a sign employers are "recognising the value of older workers".
Chris Jessop, managing director, UK and Europe, AXA PPP healthcare's health services division, said: "For businesses, having an older workforce will necessitate a more proactive approach to managing employee health because, at present, too much of the nation's workforce is not fit to age.
"Lifestyle related problems linked to lack of exercise and poor diet are the chief culprits. Without positive intervention, the bottom line could suffer as long-term illnesses, commonly occurring in tandem, take an increasing toll on performance and productivity."
The ONS figures also revealed good news for 16 to 24-year-olds, as youth unemployment fell 43,000 to 950,000. However, Martin Cook, managing partner commercial, UK and Ireland at Ernst and Young, said despite the fall there is still "little solace" to be found in these latest figures.
"The UK's young people are still bearing the brunt of the financial crisis, with the youth unemployment rate more than 15% higher than that of 50 to 64-year-olds," Cook said.
He added: "Businesses and Government need to step up to the plate urgently to avoid a potentially longer-term problem."
