A businessman at the centre of a kidnapping and violence trial has admitted he's a regular user of methamphetamine.

The admission came at the start of the second week of a trial in the High Court at Rotorua involving nine members or associates of the Head Hunters gang.

The accused are facing more than 100 charges relating to alleged kidnapping, extortion and robbery involving the businessman and a 20-year-old employee.

On trial are Benjamin Paul Dwyer, 28, Stephen William Daly, 33, Jordan Alexander Christian, 21, David Peter Clark, 36, Brent Anthony Gunning, 37, Liam John Kane, 24, Matthew John McDonnell, 45, Stacy Walton Dennis Paora, 29, and Sam Wiremu Rolleston 23.

Each has pleaded not guilty to the charges faced either with others or separately.

Referring to his P use, the businessman said he probably bought the drug more than most, either smoking it or taking it orally, often twice a day.

Pressed by Dwyer's lawyer, Tony Rickard Sims, he denied he'd supplied it to his employee.

The businessman agreed with Clark's lawyer, John Moroney, that in the weeks leading up to being surrounded and attacked at his lake retreat, he'd gone "days and days and days" without sleep.

He agreed he was requiring more and more P to stay awake and it was fair comment to say the combination of that and being woken from a deep sleep when the group burst into his house meant he had some difficulty recounting events.

He confirmed he smoked P with his captors after they'd taken him to his Taupo farm but rejected the suggestion there'd been "quite a party" atmosphere there.

He also rejected a suggestion that he suffered from delusions.