Dame Sian said Sir Robert racked up a stack of prizes as a student before going on to the University of Auckland and winning scholarships she had never even heard of.
From there it was to Oxford where Sir Robert also co-edited a legal text book while studying.
On return to New Zealand he joined the bar and was appointed a QC before he turned 40.
"He was not shy in making the point that younger appointments were necessary,'' she said.
Sir Robert went on to become a High Court judge and was appointed to the Supreme Court in 2011.
"In his work he gave the same attention to the little cases as he did to the bigger ones,'' Dame Sian said.
The congregation of family, friends, lawyers and judges of the District Court, High Court, Court of Appeal and the Supreme Court applauded.
Friend and colleague Robert Fisher QC read a statement from Sir Robert's wife Deb Hollings QC.
"We are too wrecked with our loss of Rob and Barbara to speak,'' referring to the loss of Sir Robert's sister, who died after hearing the news of her brother's death.
Ms Hollings said the couple had planned to be together for decades.
"This is the hardest thing I've ever had to do in my life. I never thought I would be doing this now.''
Auckland Crown Solicitor and close friend Simon Moore QC spoke of Sir Robert's education at Kings College.
"He described it as his south Auckland education.''
Mr Moore said the last funeral at Auckland's Town Hall was for another Sir Robert _ Sir Robert Muldoon.
"The irony would not have been lost on our Rob, and I suspect he would have had something to say about it.''
Mr Moore paid tribute to Sir Robert's "frightening intelligence'' and sense of humour. He recalled meeting his friend at the hairdresser recently.
Once back at the office, Mr Moore noticed he had an email from Sir Robert in his inbox, which Mr Moore quoted from: "Just thought I would check on how your comb-over is looking.''
Sir Robert is survived by his wife Ms Hollings, his two sons David and Chris, and step-daughters Caitlin and Zelda.
The funeral of Barbara Mitchell will be held in Hamilton tomorrow.