A Samoan chief charged with slavery and trafficking treated many of his horticultural workers "like chattels", a court has heard.

Hastings-based Joseph Matamata, also known as Viliamu Samu, who is the first person in New Zealand to face such charges, physically and verbally abused workers, many of whom were related to him, the Crown alleges.

Matamata, 65, denies 13 charges of dealing in slaves and 11 charges of trafficking, which stemmed from bringing people from Samoa to New Zealand for horticultural work across Hawke's Bay.

At the High Court in Napier prosecutor Clayton Walker said the promises made by the accused were never delivered. One complainant, out of a total of 13 alleged victims, worked for 17 months without pay.

"He [the victim] was never paid for that work, all the money he earned was kept by Mr Matamata," Walker said.

"One worker was hit numerous times by Matamata, including an assault with a stick, a power cord and a broom."

Walker said another complainant had his head smashed on the side of a table multiple times by Matamata, and also had a pair of secateurs embedded in his arm after they were thrown at him by the accused.

The prosecution alleged Matamata's claims of formalising working visas for staff also never materialised, which rendered one victim both an illegal worker and an overstayer.

Walker said when one man wasn't at work he would be kept behind a "padlocked perimeter fence" and was not allowed to talk to workmates or fellow worshippers at church on Sundays.

He said Matamata's status as a Samoan chief, or matai, meant his workers were not inclined to complain.

A matai is someone who has controlling authority and commands through his title respect and obedience. Respect and obedience is a fundamental part of Samoan culture.

"For these victims there's also a cultural sense of shame over not being paid, and being ill-treated."

The court also heard allegations of how one female worker ran away after being mistreated, but was later caught by Matamata, who then drove her back from Auckland to Hastings with her wrists and ankles bound.

Walker said to prove a charge of slavery the Crown needed to show only that the accused "treated people like property, like chattels. He was using them to fill his pockets."

It's alleged the offending spanned from 1994 to last year.

Defence counsel Roger Philip said his client denied any deception, "and he denies he enslaved anyone".

He said the trial was about "an extended Samoan family and their relationships. I'll ask you to consider how the dynamics and family relationship applies".

The jury of six men and six women was sworn in yesterday.

Justice Helen Cull is presiding over the trial, which is expected to last about five weeks and involve up to 45 witnesses.