On Thursday morning, Justice Timothy Brewer granted a Crown application, unopposed by Munro, to have the 12-year-old's case heard with his co-accused, a jury trial for which has already been scheduled to start on March 6, next year, and set down for three weeks.
Justice Brewer directed a specialist mental health report for the 12-year-old – to ensure he is fit to stand trial.
The boy was further remanded in the custody of the Oranga Tamariki chief executive.
Biggins, 62, was discovered on September 27, last year, in a vehicle that had crashed into a tree on Imms Rd, Okaihau.
Emergency service staff were unable to revive him.
The 12-year-old is one of the youngest people ever to be charged with murder in New Zealand.
Justice Brewer said interim name suppression was to continue until trial but granted the Crown and news media leave to apply to have it lifted sooner.
The case is one of three involving young Northlanders accused of murder, currently progressing through the High Court at Whangārei.