Former All Black and New Zealand Rugby Union chairman Jock Hobbs is critically ill in Wellington Hospital after battling leukaemia for more than two years.
A Wellington Hospital spokesman said this morning that Hobbs remained in intensive care.
His son Michael, a five-eighth with the Blues Super Rugby team, has flown back from South Africa to be with his father, who was admitted to hospital on Wednesday.
Blues coach Pat Lam said last night: "Michael received a call yesterday. Jock is currently in hospital and in a serious condition, so he has flown home to be with his dad and family. All of our thoughts and prayers are with Jock and his family."
Hobbs, 52, whose full name is Michael James Bowie Hobbs, played 21 tests as a flanker for the All Blacks from 1983-86. He retired from rugby in 1987 after a succession of concussions and became a businessman. He was a director of finance firm Strategic Finance, which went into receivership in March 2010.
As chairman of the NZRU, he led the New Zealand delegation to Dublin in November 2005 that secured the hosting rights to last year's Rugby World Cup.
He had to step down from his roles as chairman of the NZRU and Rugby New Zealand 2011 last May to have intensive chemotherapy. At the time, International Rugby Board chairman Bernard Lapasset described his contribution to New Zealand rugby as considerable.
Former NZRU chief executive Chris Moller, who worked with Hobbs to secure the 2011 tournament, said last night it was a "time of potential great sadness for the New Zealand rugby community".
Former All Black coach John Hart said all the accolades for the World Cup bid win belonged to Hobbs.
"When you think back to where we were in the rugby fraternity in 2003, after losing the rights, we were in disarray. Jock Hobbs and Chris Moller have rebuilt New Zealand's global reputation."
Despite his reduced role in last year's tournament, Hobbs took the field at Eden Park during the tournament to present test centurion silver caps to Richie McCaw and Mils Muliaina.
NZRU chief executive Steve Tew said: "All our thoughts and support are with Jock and his family, who have asked that media please respect their privacy at this time."
All Black Piri Weepu tweeted: "Sending my thoughts and prayers to Michael Hobbs and the family at this time ... Tough times for them, send your prayers tweeps!!"
Hobbs and wife Nicky have four children, Michael, Emily, Penny and Isabella.