Mears shook slightly as he first entered the dock, and stood with eyes downcast throughout the brief appearance before being led by police to complete bail formalities.
Prosecutor Sergeant Andrew Allerton sought leave to withdraw the original charge of recklessly using a firearm.
A manslaughter charge was laid yesterday on advice police received from a Rotorua crown solicitor.
Outside court Mr Laybourn told a media contingent that Mears had said right from the beginning he would take responsibility for what he did, even if it meant serving a jail term.
"But quite frankly, he's terrified."
Mr Laybourn stressed Mears' remorse and that he wanted the tragedy to be a lesson to others.
The officer leading the investigation, Detective Senior Sergeant Todd Pearce, said it was right for police to seek further advice about the charge.
"The circumstances of Ms Ives death were different from what Police normally deal with in most hunting related incidents and deaths, so it was important that additional advice and review was sought.
"It is also appropriate that we consider the legal advice we receive, and act on it as we have in this instance."
Ms Ives had gone to the Kaimanawa Ranges for a rock-climbing trip with her boyfriend, Adam Hyndman, and was brushing her teeth when Mears shot her.
He told police that he mistook Ms Ives for a deer while spotlighting from a moving vehicle with three friends.
- With NZPA