The number of complaints made about NHS care in England increased to an average of 480 every day, official data shows.
The Health and Social Care Information Centre (HSCIC) figures showed a total of 174,872 complaints in the 2013-14 year.
The complaints cover all aspects of the NHS from hospitals and GPs to dental practices and ambulances.
However, a patients' watchdog said the official figures were just the tip of the iceberg.
In 2012-13 there were 162,019 NHS complaints and 131,022 in the 2007-08 financial year.
Due to a change in the way the data was collected, so HSCIC does not know how many GP practises reported complaints in previous years so it is unclear how comparable the figures are.
The most complaints - 34,400 - were focused on inpatient hospital care.
The largest percentage increase in complaints was for ambulance crews - up 28.5% to 5,700.
'Pay close attention'
Kingsley Manning, the chairman of the HSCIC, said: "Our latest figures show that the NHS is receiving a large number of written complaints each day.
"Today's report also shows a rise over the last year in the number of written complaints made against NHS hospitals and community services.
"I'm sure staff who manage NHS complaints will want to pay close attention to these statistics."
The patients' watchdog Healthwatch England said most people do not report poor care.
A survey by the body suggests there were 500,000 unreported cases of unsatisfactory patient care across the NHS in the past two years.
Anna Bradley, the chairman of Healthwatch England, said: "The report out today really is just the tip of the iceberg when it comes to complaints about health and social care services in this country.
"The need to improve the way the complaints system operates is well documented and we have been working with the government to simplify the often baffling process for patients and their families.
"But for things to work properly, health professionals clearly need to do more to make people feel less intimidated about making their voices heard."
A Department of Health Spokesperson said: "We welcome the fact that more people have felt able to raise their concerns with hospital trusts, as listening to patients is one of the best ways to improve standards and this has been a priority in the wake of the appalling events at Mid Staffs."
They called for a "culture of openness" in hospitals where it was clear how patients could complain.