Tests will determine whether rugby star's failing transplanted organ can be revived.
Dialysis will buy Jonah Lomu as much time as needed for his kidney to be revived, or to get a re-transplant.
He's in Auckland Hospital's renal ward, with doctors reportedly saying there's a slim chance his donated kidney will survive.
Professor of Transplant Surgery at Auckland City Hospital Stephen Munn says donated kidneys don't last forever.
He says there's no time limit for a person to be on dialysis as it's the next best thing to having a fully functioning kidney.