Lomu died on Wednesday from a cardiac arrest brought about by a debilitating kidney disease he had battled for 20 years, his former New Zealand coach John Hart, acting as the family spokesman, told reporters in Auckland.
"This is an incredibly sad time for all of us," he said as Lomu's family and former All Blacks team mate Michael Jones stood behind Hart outside his home in Auckland.
"There will never be another Jonah Lomu. It's just one of those things ... that took a great man from us."
Local media reported that Auckland's Eden Park was being considered for the public memorial service, which Hart said was possible though the family were still in discussions with central and local government about what was "most appropriate".
"I am delighted with the tremendous support we are getting from government and local government to celebrate Jonah's life, Hart added.
"We have agreed that there will be a public memorial service and that will be followed by a private family church service."
Hart added that Queen Elizabeth had asked Prime Minister John Key to pass on her condolences.
The former All Blacks coach added that Lomu's wife Nadine was "struggling" to deal with his death but their two young sons were coping.
Lomu's father-in-law Mervyn Quirk had earlier issued a statement acknowledging the public for their support.
"We wish to thank all the people who have expressed their sympathies for our family at this incredibly difficult time," Quirk said in a statement.
"We are truly touched by the outpouring of love for Jonah and the support for our family.
"While we grieve for a husband, father, son, brother and good mate, we know that many people in New Zealand and around the world are mourning a very special individual."
(Reporting by Greg Stutchbury in Wellington; Editing by Ken Ferris)
