The family of Kai Sakakibara has released an update on his condition following the UCI BMX World Cup round in Bathurst on Saturday.
The Australian Olympic hopeful was injured during the heats on Saturday, with the 23-year-old falling on the second corner of the track.
He was assessed and treated onsite for head injuries by paramedics and a doctor, before he was taken to Canberra Hospital by helicopter in a critical, but stable condition.
A statement released by the Sakakibara family said he had an operation on Sunday morning to relieve pressure on his brain.
"He has been placed in a medically induced coma to help his body relax," the statement said.
"Kai's condition is described as critical but stable, he is in good hands and under 24-hour monitoring. We are expecting he will remain in a medical coma for the next two weeks or so.
"We understand the road ahead will be a long and difficult one, we are staying positive and taking things day by day.
"There isn't much we can do at this point but Kai needs your support and your positive energy sent his way.
"Please keep thinking of Kai and stay with us on his journey for the months ahead.
"For now, we are waiting to see how things progress and our focus is on his long-term rehabilitation. Kai's BMX career will be put on hold for now.
"This is a very difficult time for all of us, but we felt it is important to share what we know at this moment."
No further updates on Kai's condition are expected to be provided for at least the next two weeks.