"On behalf of the judiciary I have issued a statement of condolence recognising her life of extraordinary commitment to duty and unprecedented service as Sovereign."
Courthouse flags will fly at half-mast and a decision was made to keep courts open today, the statement said.
"The judiciary has a plan in place for this day, and I write to advise you of it now.
A ceremony at the Auckland High Court in 2006 appointing Bruce Gray and Brian Keene to the Queens Counsel.
"Judges have been invited to mark the event in court in a manner of their own choosing – for example with a short statement of condolence, a karakia that has been prepared to mark this event, or two minutes silence."
"As a matter of law and constitutional practice, the Crown is never vacant," the statement said.
"The new monarch accedes to the throne immediately upon the death of his or her predecessor."
The Governor-General appoints QCs / KCs from the ranks of lawyers "in recognition of their extraordinary contributions to the field of law", according to the NZ Bar association.
The awarding of the title, informally known as "taking silk", carries huge prestige and allows barristers to command significantly higher fees.
The change to KC has become the source of amusement among some in the legal profession on Friday, given it is the frequently used abbreviation for one of New Zealand's oldest and largest patched gangs, the King Cobras.
From 2007 to 2009, the title of QC was briefly abolished, being replaced by "Senior Counsel".
In 2009, then Attorney-General Christopher Finlayson, himself now a KC, announced the new Key Government was restoring the QC title.
Speaking to the Herald after the change was announced, Finlayson explained the reason for the immediate change.
"The rationale for it is you can't be a counsel to a dead monarch."
Finlayson said the brief change to SC was unpopular in the legal profession, and most of the small number who gained the title converted back to being QCs.