Hiroki's defence lawyer, Simon Hewson, said his client admitted some involvement in the incident but not direct involvement.
"He claimed to have no knowledge of the accident when it happened — he was only going 85kmh and did not see it happen," Mr Hewson said.
The lawyer said it was suggested Hiroki was overtaking his friend and that had caused the accident, but he denied the accusation.
"There are other riders of the motorbikes that have not been identified, and that is a core issue there in itself," Mr Hewson said.
At the time of the crash, police said they were interested in sightings of three motorcycles travelling southbound on SH1 between Taupo and Bulls.
Hiroki was arrested by police that day and granted bail on November 13 to a remote address.
He has been charged with one count of driving causing death, two counts of failing to stop or ascertain injury, three counts of dangerous driving causing injury, one count of driving in a dangerous manner and one other unspecified charge.
Judge Philip Crayton remanded Hiroki on bail for a case review hearing on April 10 in the Whanganui District Court.
A judge-alone trail was elected.
