Jock Hobbs in hospital

New Zealand rugby legend Jock Hobbs has returned to hospital and is in a critical condition after a deterioration of his leukaemia.

Hobbs is a former All Blacks captain and former New Zealand Rugby Union chairman up until his health forced him to step down from his post.

Blues flyhalf Michael Hobbs, Jock's son, has flown home from South Africa where he was on tour with the Auckland side to be at his father's bedside.

"Jock is currently in hospital and in a serious condition," NZRU Chief Executive Steve Tew confirmed. "All our thoughts and support are with Jock and his family."