A parliamentary watchdog investigated double the number of complaints about government departments in the past year than in the previous 12 months, a report has said.

Figures in the annual report from the Parliamentary and Health Service Ombudsman showed that 107 grievances were taken on for a full probe in 2010-11, compared with 52 the previous year.

In total, the ombudsman received 23,422 enquiries from members of the public, including 6,990 about parliamentary bodies, 13,625 about the NHS and 2,807 about bodies outside its jurisdiction.

Among the total number of complaints about the health service, the most were about acute trusts (6,924), with 2,714 about primary care trusts and 2,581 about GPs.

The Ombudsman made 296 complaints subject to a full investigation.

Of these, 177 involved hospital, specialist and teaching trusts (acute), 66 were about GPs, 54 about primary care trusts, 22 referred to dentists and 20 to mental health, social care and learning disability trusts.

The total is greater than 296 because one complaint could affect two different sectors.

Ombudsman Ann Abraham said: “We take time to advise and assist people with making a complaint, and to find swift and direct solutions where possible. As a result, only a few hundred of the complaints we resolved last year needed a formal investigation.”

Among the grievances that were investigated, 79% about health bodies were upheld, as were 78% of those about parliamentary bodies.

A Department of Health spokesman said: “The revised plans we set out last month, in response to the independent NHS Future Forum, will safeguard the future of the NHS and put patients at the heart of our health service.

“Under the plans, patients will have a stronger voice and the NHS will be more accountable for the quality of care it provides for patients.

“In addition, Local HealthWatch will champion the views and experiences of patients, helping to drive improvements in the quality of health and social care services.”