Museum director Raymond Seymour said the sentencing was fair.
"I think it was an appropriate sentence for this cruel and calculating criminal," Colonel Seymour said.
Sentencing the defendant, Judge Graham Hubble said the court took a dim view of dabbling in national treasures and holding them to ransom. He said he gave the man a discount for entering an early guilty plea, returning the medals and the ransom, and the fact that he stood up in court yesterday and apologised.
The defendant told the court he did not mean to target anyone individually.
"I apologise to all servicemen past and present who served for this country. I did it for my own personal gain and I sincerely apologise for everything I've done," he said.
Several victim impact statements were presented to the court, and Colonel Seymour spoke about the effects on him personally, as museum director.
"In my mind this is a crime that shocked the nation, who were so angry that anyone could have the audacity to commit this heinous crime.
"This crime has torn the heart out of every New Zealander," he said.
He said he spent a week of his Christmas break scouring the sides of State Highway 1 in the hope that the medals had been discarded.
He said he had tears in his eyes when the medals were returned to the museum the following October.
Amanda Upham, daughter of Captain Charles Upham, also spoke about the impact of the incident.
The medals stolen included her father's Victoria Cross Award and Bar, the only such medal ever awarded to a combat soldier, and the only such medal awarded in World War II.
Judge Hubble said the five-year prison sentence for 50 other fraud and burglary charges should be served cumulatively with the six-year term for the medal theft.
This offending involved identity theft on a large scale with the use of computers to access personal details and the use of forged passports.
The man was currently serving a term of two years, three months' imprisonment, due to end in December.
This jailing followed his pleading guilty to the theft of a Goldie painting and some poems of Colin McCahon from Auckland University. The man was planning to ransom the painting.
He agreed to return the painting if six charges in relation to the university were dropped. Judge Hubble said this was not looked on kindly by the court at the time.
"Here you are again stealing icons, which required extensive planning and premeditation by a person who is obviously intelligent.
"The sheer volume of your offending is mind-boggling ... Millions of dollars have been involved, and you have caused extensive damage to financial and business institutions," Judge Hubble said.
- NZPA