More than a quarter of a billion pounds could be being wasted to fraud every year across Northern Ireland's health service.
The staggering cost – enough to fund a new state-of-the-art hospital – was revealed by Health Minister Edwin Poots as he launched a campaign aimed at tackling the problem.
The most common examples of fraud include staff falsifying the number of hours worked, overclaiming travel expenses and fraudulently attempting to obtain prescription medicine.
In a growing number of cases, people living in the Republic are hopping across the border and falsely claiming to be resident to secure free treatments.
Mr Poots said: "Fraud is not a faceless crime, especially in the health service, it affects us all.
"It is a criminal offence and every penny lost means less to spend on front line services.
"Whether it's £1 or £1m, fraud robs the health service of vital resources."
Whilst the true extent of fraud is not known, independent research across the health sector in other countries suggests it may be between 3% and 7%.
Mr Poots added: "Taking the highest possible figure, that equates to almost a quarter-of-a-billion out of a total health and social care budget of around £4bn, which is not available to invest in front line services."
He said the money could pay for 26,453 coronary heart bypass procedures, 388,350 cataract surgical procedures, 38,525 hip replacements or 7,000 patients receiving renal dialysis treatment.
He said £280m could also build a fully equipped hospital such as the new South West Area Hospital in Enniskillen. the minister added.
Several examples of fraud are cited in a paper compiled by Department of Health experts.
A very detailed and complex investigation led to the successful prosecution the two directors of a company delivering mobile eye services.
Both were given suspended prison sentences.
A repayment of around £40,000 was made to the health board.
In another case a man living abroad but treated in Northern Ireland owed the NHS £27,000.
He was married to someone who lived locally, had spent a period in the region and had been registered with a GP, the gateway to hospital services.
He moved to the United States but returned for free health care.
Other fraud involved incorrect staff expenses claims, for example nurses who travel to visit ill people in the community may claim for journeys not taken or hours not worked.
During the 12 months to March, 107 cases of suspected fraud or error were won in the small claims court by the health service.
However, Mr Poots said a greater public role was needed in tackling the issue.
"I acknowledge that there is already a significant amount of counter fraud work being undertaken across the health service and that a caseload of some 100 cases was under investigation in 2012/13, which has resulted in a number of criminal prosecutions and financial recoveries," he added.
"However, everyone has a part to play in stopping fraud.
"It's not just for the experts in the Business Service Organisation to detect and fix – it's not just for the accountants and lawyers – all members of staff, from clinical and non-clinical, admin to management, including doctors, dentists, nurses, optometrists and pharmacists, have an important role to play in combating fraud.
"It is therefore everyone's duty to report fraud or suspected fraud – whether that's through the fraud hotline, through the online reporting tool or indeed through your organisation's whistleblowing procedures.
"I also believe it's important for the general public to play their part – after all, it is their money that is being wasted to fraudulent activity."
Mr Poots was speaking ahead of Fraud Awareness Month, which is launched today in Belfast.
Health organisations must report all instances of actual or suspected fraud, including theft, via the regional fraud reporting system. Some 132 reports were received during 2012/13. Thirty-four (25%) involved theft and were referred directly to the PSNI. The Health and Social Care Board reported 56 cases, an increase of 70%