Lomu, 40, died on Wednesday at his home in Auckland. He had been battling a rare kidney condition since 1995.
"We wish to thank all who have expressed their sympathies for our family at this incredibly difficult time," Mervyn Quirk, Lomu’s father-in-law, said in a statement.
New Zealand PM confirms Lomu memorial details
"We know that many people are mourning a very special individual.
"We are truly touched by the outpouring of love for Jonah and the support for our family.”
Lomu played 63 times for the All Blacks during a career that was disrupted by his health battles, scoring 37 tries in the process.
Quirk said that the family were still in the process of finalising funeral arrangements.
Tributes pour in for Jonah Lomu: 'A freak, a nightmare and the nicest, nicest guy'