The National Diabetic Retinal Screening Programme repeatedly sent letters to a dead woman, asking her to take part in a medical scan programme.
Richard Barton, from Tinahely, Co Wicklow, has branded the government-funded organisation "vultures" after it sent letters to his dead wife, Miriam, even after he told it to stop.
On one occasion, after Mr Barton had already explained that his wife was dead, she received a reply acknowledging her unwillingness to participate in the programme and telling her what to do if she ever changed her mind.
Mr Barton said his wife died in 2015 at the age of 61.
He was surprised to get a letter in January from Diabetic Retina Screen asking her to take part in an eye scan programme.
"I wrote back to them and told them Miriam had died and then three weeks later I got a final reminder addressed to her through the door," Mr Barton said.
"I wrote back again rather angrily to the person who sent the letter. It was the same person named on the first letter, and even sent them a copy of my first letter and again explained the situation.
"Three weeks later I received a curt apology and a promise that they would update their records, and I thought that was it.
"Then I was halfway between upset and furious when I got a letter dated April 7 from the same person, which acknow- ledged Miriam's unwillingness to participate in the programme and telling her what to do if she ever changed her mind."
The letter, which has been seen by the Herald, was add-ressed directly to Mrs Barton.
"Thank you for letting us know you will not be participating in Diabetic Retina Screen - the National Diabetic Retinal Screening Programme," it read.
"We will not send you any further letters or correspondence from the programme.
"If at any stage you wish to participate in Diabetic Retina Screen or have any further queries, please contact us," the letter concluded, adding a contact phone number and website address.
Mr Barton has now contacted the screening programme again and copied the letter to Health Minister Simon Harris to make him aware of the situation.
"Your horrible little organisation disgusts me. In fact, the word 'organisation' is barely applicable to you," he wrote.
"You are clearly just desperately hoping to be able to show lots of people they are unwell. 'Illness vultures' would be a good description."
Mr Barton said if his wife was even the slightest bit known to the company, they would have known she had died 21 months before they sent the test suggestion.
"After receiving my first letter, they might have apologised. Instead, she was sent a final reminder," he said.
"After receiving my next really angry letter, they should have apologised. However, clearly to me, they are interested in nothing except more business."
Mr Barton, who has qualifications in counselling and nutritional medicine, blasted the health service in Ireland, branding it an "illness service".
Diabetic Retina Screen told the Herald it sincerely apologises for any distress that the letters caused and understands the sensitivity of the situation.
"Given that the reliability of the diabetic retinopathy register is dependent on the reliability of its sources, we fully acknowledge that such a population register will inevitably contain inaccuracies," it said.
"We are currently investigating how the last letter as mentioned was issued.
"It was clearly sent in error and we would reiterate our apology for the distress this has caused."