UPDATED 10.21am: Alex Fisher's older brother has pleaded guilty to his murder.

Eric McIsaac has appeared in the High Court in Palmerston North this morning, where he's admitted killing 10-year-old Alex in Waitarere Beach last October.

Newstalk ZB reporter Georgia Nelson was in court for the brief appearance.

She said a lot of details of the hearing have been suppressed, but she can reveal that there were many family members in court, and they were very distressed by the proceedings.

Alex's family were in the public gallery.

Justice Joe Williams acknowledged the family: "I understand this is a very difficult time for you...I salute your courage."

Alex's mother cried throughout the proceeding. 

The body of Alex Fisher  was found on Waitarere Beach in October following a three-day search.

McIsaac also pleaded guilty to having unlawful possession of a knife in a public place and burglary. 

Police will be making no comment until the conclusion of the court process at sentencing. 

He is remanded in custody until July.