The 34-year-old former All Black and his partner Alana Madill died in a car crash on a motorway near Beziers in southern France early on Friday morning (local time).
The couple's four-month-old daughter Ayla is fighting for her life in intensive care at a hospital in Montpellier.
Collins' longstanding agent and family spokesperson Tim Castle said today the situation was "precarious", with no change in Ayla's critical condition.
"It's fair to say without wanting to be dramatic, in fact quite the contrary, that it is precarious. It's very serious. To the extent that there's no change is an update of a sort."
Mr Castle said there was a lot of paperwork to get through before Collins' body could be repatriated and he was avoiding any speculation on how long the lengthy formal process would take.
France-based All Blacks Neemia Tialata and Chris Masoe had dressed Collins for his journey home, Mr Castle said.
"It was very comforting to the family. It's like the boys were their representatives with Jerry getting him ready for the journey home. It meant they could kind of reach out through them to their son.
"It brings them even closer to him, even though they would obviously like to be closer still."
No funeral arrangements could be finalised before the repatriation was organised, Mr Castle said.
The family would be taking the significant public interest into account with any decisions they made, he said.
"The family will of course do a number of things privately but they're very aware and very grateful for the support and sympathy and very public expressions of affection for their son. That's figuring in with their considerations."
According to local media reports, the couple's car was hit by a bus. An autopsy on Ms Madill, who was driving at the time, was due to be conducted today to help determine the cause of the accident.
Prime Minister John Key paid tribute to Collins today. "It's very sad," Mr Key said on television. "He's someone who earned our respect on the rugby field."
A Ministry of Foreign Affairs and Trade spokeswoman said a New Zealand Embassy representative had travelled from Paris to Montpellier to facilitate the repatriation of Collins' body.
It would not be providing any further information out of respect for the family's wish for privacy, she said.
The Jerry Collins Memorial Fund has raised over $21,000 for Ayla Collins in just two days.
