Former All Blacks and Chiefs back-row Sione Lauaki died in Auckland on Sunday, apparently suffering from kidney failure.
He was 35 years old.
New Zealand Rugby chief executive Steve Tew expressed his condolences to the family.
"We are incredibly saddened by this news, as will be many who have known Sione through both his rugby and Tongan community connections," he told the All Blacks' official website.
"It is always sad to lose a member of the All Black community, but with Sione passing at such a young age it will be felt with an even greater sense of tragedy amongst his former teammates, fans, family and friends."
The family have asked media to respect their privacy and have asked them to give the family time and space to mourn their loved husband, father, brother and friend.
Lauaki played 17 Test matches for the All Blacks between 2005 and 2008. In 2012, he was diagnosed with kidney and cardiovascular ailments which forced his retirement.