An 80-year-old man died in hospital after waiting 23 hours for an ambulance and a further seven hours before being admitted, his son has said.
Darren Williams, 48, said his father John Williams died on Sunday, four days after being admitted to Morriston Hospital in Swansea, South Wales and five days after he fell at home, last Tuesday.
Mr Williams said he called 999 that morning but an ambulance did not arrive for 23 hours.
His father was then forced to wait another seven hours in the back of the ambulance outside the hospital before he could be admitted.
"I can't help thinking that all this has contributed to my father's passing," he said.
"What should have happened in my view is a rapid response paramedic should have been with my dad within 40 minutes to an hour.
"He should have been assessed on the kitchen floor and they could have made the call from there.
"He might still be with us. It is just unbelievable.
"How many people are going to lose their lives through this? Sooner or later it is going to be a child."
The Welsh Ambulance Service has said a full investigation will be carried out into the incident while Abertawe Bro Morgannwg University Health Board, which runs the hospital, said Mr Williams had been taken to hospital with minor injuries.
Mr Williams said he went to his parents' home in Gowerton, Swansea, after his mother phoned to tell him his father had fallen in the kitchen and was on the floor.
Mr Williams dialled 999 at about 8.25am, expecting a wait of an hour or so.
He said he called again two and a half hours later, and twice more, but an ambulance did not arrive until 7.30am on Wednesday.
Mr Williams said his father was conscious but confused while lying on the floor and after 11 hours there, they decided to move him.
He said: "Myself and my brother decided enough is enough, so against obviously medical wishes we picked him up because it was ridiculous.
"We sat him in his chair and he went to sleep.
"Obviously he hadn't had medication when he was admitted to hospital, that would have been about 36 hours, which equates to probably over 30 tablets.
"We were told not to give him any medication."
Mr Williams believes this could have contributed to his father's death because some of the tablets were for his heart.
After his father died, Mr Williams said he was told it was due to lack of oxygen and his heart "gave up".
He said the ambulance crew, when they arrived, were "brilliant" and "just trying to do their job in a very difficult situation".
Mr Williams said that about two hours after his father was admitted, the hospital wanted to discharge him.
He said: "I said 'I want it put on the record that he is not right, he has obviously fallen for a reason, we'll be back here tomorrow and we'll have the same scenario again'."
Mr Williams said he went to collect his vehicle but while he was gone his father fell again and the decision was made to keep him in.
"He seemed fine," he said.
"I was with him Saturday night and on Sunday morning when I saw the no-caller ID on my phone I thought it's obviously a phone call to arrange to come and pick him up on Monday morning, not to be told 'get here fast he is short of breath'," he said.
Mr Williams said his father died at the same time the call was made, 9.45am on Sunday.
Of the ambulance service he added: "Those crews are doing two calls a day because they are stuck outside the hospital.
"It is shocking."
Claire Bevan, director of quality, safety and patient experience for the Welsh Ambulance Service, said: "We would like to extend our sincere condolences to Mr Williams' family at this very sad and difficult time.
"We want to ensure a full investigation is carried out into the wait that Mr Williams experienced and we will be communicating with Mr Williams' family."
An spokeswoman for Abertawe Bro Morgannwg University Health Board spokeswoman said with the permission of Mr Williams' family, she was able to explain a bit about Mr Williams' condition and care.
She said: "Mr Williams was brought to Morriston Hospital with minor injuries after a fall at home.
"Following a thorough assessment and observations in the Emergency Department, doctors couldn't identify a reason for this fall.
"However, later on, Mr Williams' general condition began to deteriorate and due to this doctors then decided to admit him to a ward for further tests and observation.
"Unfortunately, Mr Williams' health continued to deteriorate; staff did all they could to treat him but sadly he died a few days later."
She urged the family to contact the health board with further queries or concerns about his care and added: "We would like to offer our sincere condolences to Mr Williams' family and friends."