As few as 5% of errors relating to patient safety are ever reported, according to new research led by former health minister Lord Ara Darzi.
While the UK has one of the biggest systems in the world for reporting incidents, the "culture of institutions and the culture of medicine" puts staff off reporting errors for fear of being blamed, experts said.
They added that patients are at increasing risk of harm, with older people suffering more complex illnesses potentially leading to more errors, budget cuts putting staff under pressure and the increasing threat of simple infections becoming resistant to antibiotics.
The two new reports come after the NHS staff survey last month found more than a quarter of health service workers do not believe their hospital learns from errors.
The poll of 299,000 NHS staff - around a quarter of the permanent NHS workforce in England - also found a lack of confidence that whistleblowers and those involved in incidents will always be treated fairly by their NHS trust.
In the new studies, experts from Imperial College London said the NHS system for reporting errors was not sensitive enough and needed an overhaul.
They also pointed to the NHS culture as a barrier for improving reporting. Fear of blame by peers and managers has been linked to "apprehension of reporting harm and potential problems," they said.
They added: "Culture counts. Health systems and organisations must truly prioritise quality and safety through an inspiring vision and positive reinforcement, not through blame and punishment."
Meanwhile, budget cuts - including asking doctors and nurses to "do more with less" - could drive up the number of errors, they added.
"Sustained spending pressure coupled with tighter budgets will likely generate large gaps between healthcare needs and available resources; this gap could have large consequences for patient safety," they said.
"A response to constrained budgets is to try to do 'more with less'. However, this type of approach, if not carefully devised, could have an impact on patient safety."
Lord Darzi, senior author of the reports and director of the Institute of Global Health Innovation at Imperial, said: "For too long the mindset has been that patient harms are inevitable, and that nothing can be done to prevent them.
"But keeping patients safe is a fundamental part of care. Although we currently face many changes – such as increasingly complex patient cases and limited resources – we must focus on creating safer environments for patients."
He added: "We also must ensure patients and staff are integral to any solution, and not just seen as victims or culprits."
Erik Mayer, report author from the department of surgery and cancer at Imperial, said: "The UK has one of the biggest incident reporting systems in the world.
"But despite this, evidence suggests that as little as 5% of patient safety incidents are reported. This is often related to the culture of institutions and the culture of medicine. For instance, staff may witness an incident that should be reported, but are hesitant to do so for fear of repercussions."
Mr Mayer said the information produced by the NHS error reporting system is difficult to analyse, making it hard to spot dangerous trends or problems.
He said: "At the moment there is no standardised method to code or group the reports.
"So, for example, a delay in a medication being given may be recorded in a number of different ways, depending on the hospital. We need to standardise this and ensure that we have an improved approach to incident reporting."
The most recent NHS data shows that more than 600,000 patient safety incidents have been reported in acute hospitals in England in a six-month period.
In the six months from October 1 2014 to March 31 2015 there were 621,776 patient safety incidents.
Of these, 20,827 caused moderate harm and a further 2,373 caused severe harm. Some 716 patients died as a result of incidents and mistakes.
Dr Peter Lachman, clinical lead for the Safe programme at the Royal College of Paediatrics and Child Health, said: "At a time when there are an estimated 2,000 healthcare and non-healthcare related preventable deaths a year in the UK, it is absolutely vital that we all make a concerted effort to see these figures drop.
"We know that problems can arise from something as simple as varying quality in communication between hospital staff and patients. And as these reports both point out, a more transparent and shared culture is what is most needed to help reduce avoidable error in patient care."