A report from the Parliamentary and Health Service Ombudsman has found that though over-65s are more likely to need health care, they are reluctant to complain about poor services.

Over half – 56% – of those who had experienced issues did not complain because they were worried that doing so would affect their future treatment; and a third thought it would not make a difference.

Nearly a fifth – 18% of over-75s – didn't know how to make a complaint about the NHS or another care provider. The findings come after a national survey of 4,263 people, 689 of whom were over 65.

Parliamentary and Health Service Ombudsman, Julie Mellor said: "Older people are some of the most frequent and vulnerable users of health and social care services but are the silent majority when it comes to complaining. Their reluctance to complain could mean that they are suffering in silence and could lead to missed opportunities to improve the service for others. We want older people to be confident to speak up when things go wrong to help prevent someone else from going through the same ordeal."

The report, Breaking Down the Barriers, mentioned that services moving further online is leaving older members of the public out of the loop. A participant in a Poole focus group said: "They will say to you 'email me' but older people don't have a computer... I don't want to use a computer." Only 17% of those aged over 75 had found out about the ombudsman online.

The report suggested that older people prefer to mention issues informally because they "didn't want to cause a fuss" but that it was important older people felt able to complain formally if necessary.

The Parliamentary and Health Service Ombudsman makes final decisions on complaints that have not been resolved by the NHS.