The former All Blacks captain and rugby union chair Jock Hobbs is in a critical condition in Wellington Hospital.
Mr Hobbs, 52, has been suffering from leukaemia.
He stepped down from his position at the New Zealand Rugby Union in order to undergo treatment for the cancer in 2010.
A hospital spokesperson said Mr Hobbs was admitted to the intensive care unit on Wednesday.
His son Michael, who plays for the Blues, has flown back from South Africa.
During his time as New Zealand Rugby Union chairman, Jock Hobbs was pivotal in the successful bid for the 2011 Rugby World Cup.