The only palangi in the room, I had been invited by Tongan community leader Melino Maka, who was keen to speak about the place of kava in the culture here.
I'd initially called him to follow up a news report that Goodman Fielder was planning to drug-test workers at a Dunedin site for kava, though the company says it's untrue and the Drug Detection Agency says no test for kava intoxication exists yet.
Certainly nobody at the Saturday evening event looked even slightly the worse for wear - not something you could say about every party in town that night.
Ha'unga Petelo, who was at pains to deny he was in charge, told me the evening was called a fofo'anga, a word whose metaphorical significance became more obscure to me the more he explained it: we settled on kava club.
"It's just a gathering," he said, "and it's part of the Tongan custom. People come and have a kava, talk about the day and relax and when they've had enough they go home and sleep."
When I told him I had only tried kava in Vanuatu, he flinched. "That kava is too strong," he said solemnly. "I think they make that kava for a horse."
Mildly sedative and anaesthetic, kava, made from the roots of a shrub, is a social lubricant with a long tradition throughout much of the Pacific. "Nothing in Tonga happens without kava," Petelo says, even (perhaps especially) on formal occasions, when a cup or two is mandatory.
The atmosphere at the fofo'anga, however, is anything but formal. Maka says that the gatherings, held each Saturday, provide a chance for young Tongan men, many of whom are New Zealand-born, to "reconnect with their culture".
"It is better for them to be sitting around and listening to their elders and learning about who they are than to be out there drinking alcohol and abusing other substances. Look around here. These young men come here because they want what is here."
In this relaxed environment distinctions of social status are erased. Tongan society is famously hierarchical and Maka, who works implementing Whanau Ora programmes in Tongan communities, says kava oils the wheels of communication.
"Part of getting people to discuss things is sitting round having a kava. You get people there of very different status - church leaders, other ministers and ordinary people. In order for everyone to talk on the same level, they have to have a kava. Then we can talk."
Ben Langi, a counsellor from the Problem Gambling Foundation, who delivers a stern-sounding lecture on the dangers of gambling, agrees. "A gathering like this underlines our unity. We are able to come here and talk at a level where everyone is the same - and kava is important to that."
Needless to say, all three men think that kava-testing would be a catastrophe because it would create the idea of a problem with a substance that was a force only for social good.
Says Maka: "They don't realise the implications. It would create a stigma in our community by associating kava with breaking the law."
They concede that abuse of kava is possible, but very rare. By contrast, an AUT study last year showed that young Tongan men who attended kava clubs were less likely to be involved with drugs, alcohol and gangs.
"You don't get binge drinkers of kava," Petelo says. "Look at the records. You won't find any accidents because of kava."