The offences related to 13 people brought from his home community in Samoa to work in New Zealand over a 25-year period from 1994 until 2019.
The High Court trial was told that Matamata had abused his status in the Samoan community, where he held the chiefly title of matai.
He falsely promised the Samoans that the money they earned would be theirs after they had repaid him for bringing them to New Zealand and for lodging at his property, this week's Supreme Court decision said.
"But, although they undertook the work required of them, [Matamata] retained their income, restricted their freedom of movement, restricted their communications and used actual or threatened violence for breaching his rules or standards," it said.
Matamata first appealed his convictions to the Court of Appeal, but was turned down. He then sought leave to appeal to the Supreme Court, and that has now been denied.
Matamata's lawyers argued that the Appeal Court was wrong in determining the legal definition of "slave".
They also disputed that the High Court jury had been properly directed about what human trafficking meant.
The Supreme Court justices Sir William Young, Sir Mark O'Regan and Dame Ellen France disagreed on both counts.
They noted that the trial judge directed the jury that a slave is a person held as property, "meaning that the person is subject to controls tantamount to possession", and which "significantly deprive" a person of liberty.
Matamata's lawyers argued in the Appeal Court that the jury should have been told the essential element of the offence was to "entirely deprive" someone of freedom and liberty.
The Appeal Court rejected this argument and the Supreme Court justices saw no error in this.
"As the applicant's counsel accepted, the authorities and academic literature treat control (defined by reference to possession) as a proxy for slavery," the decision said.
"We do not consider any matter of general or public importance arises and we do not consider there is any risk that a substantial miscarriage of justice may have occurred."
A separate earlier appeal by the Crown set Matamata's non-parole period at five years. The names of his victims are permanently suppressed.
