Lomu is barely able to walk

The former New Zealand winger said a kidney had been offered to him by a relative but that doctors had warned that he was not a good donor.

"We are travelling down the road with a relative but he has complications," Lomu told BBC Radio Five Live.

"One of my relatives went in to donate his kidney but he can't do it because his body mass is too big."

Incredibly, Lomu, who was told early in his career that he might have a kidney failure, has not given up on the possibility of a playing comeback.

"I definitely haven't given up hope," he said.

"I just want to finish on my own terms, so I have that choice and I've got that option.

"I had nine good years of playing rugby after being given that warning but I have some unfinished business and I will be giving my all to play again."

Lomu has trouble walking due to the dialysis treatment he receives six times a week, and a nerve specialist has advised him that he might not walk again in time.

The All Black took most of 1997 off for treatment for the rare kidney complaint and returned later that year.

But he failed to get fit enough for the 2003 World Cup, completing just three Super 12 matches last season before his illness flared up again.