A family's hopes that a son would be able to donate his kidney to his dad have been dashed.

Stuart Hillary, 21, decided to donate his kidney to his father Edmund Hillary, 60, who has suffered with kidney problems for the last 19 years.

Edmund had a transplant 15 years ago but his body rejected it in 2015, leaving him with just five per cent renal function.

He was put back on dialysis three times a week, which drains all his energy and has dramatically decreased his quality of life.

But early last year, when Stuart decided to give one of his kidneys to his dad, the family were buoyed up by hope.

They were told the operation would most likely happen in the last week of December or beginning of this year.

Edmund was looking forward to a new lease of life free from dialysis.

Because the donation was from a living person, it would also last for his lifetime; unlike donations from those who have died, which generally last about 10 years.

But just weeks before the operation was scheduled to take place, doctors told Stuart and Edmund that the operation is too risky because of the possibility Stuart's remaining kidney could fail in the first 10 years after the operation.

When Amanda Hillary, 42, Stuart's mum and Edmund's wife, found out, she burst out crying.

She said: "I think it's totally knocked [Stuart].

"He put his life on hold for a year. It just feels like he's lost that year and he feels like he's let his dad down because he can't do it."

The news has also been a serious blow for Edmund.

Amanda said: "He's not well at all. He just won't do anything.

"He hasn't got any energy left. When he comes home from [dialysis], he's absolutely shattered.

"The next day he seems to be getting better but then he's got to go back on dialysis again."

Before his donated kidney failed, Edmund used to play golf and squash.

But now he has no energy for sports and has to watch what he eats and drinks.

The family are now waiting for a phone call in case a suitable transplant from an organ donor becomes available.

They have been through this tense waiting game before.

Edmund waited for three years before his last call in 2001.

Towards the end he was doing dialysis at home three times a day and was basically bed bound.

Amanda said: "I'm trying to keep it together for the pair of them.

"It's very difficult trying to think how it's going to pan out and when he's going to have a phone call.

"To be honest we thought it could have been over and done with by now.

"It hasn't worked out that way so we're seeing what's going to happen now."

The family feel especially frustrated that their hopes were raised for a year only to be dashed.

Amanda said: "We have just got to take it. We have just got to get on with life.

"There's worse off people out there than us. We just hope and pray that something happens soon."