Film-maker Tearepa Kahi directed the 2013 hit Mt Zion starring singer Stan Walker. His documentary Poi E: The Story of Our Song debuts at the NZ International Film Festival this month in time for Matariki, the Maori New Year.

1. Poi E was the first Maori language song to make it to No1 in the charts. Why did Pakeha New Zealand adopt this song as their own?

Whether you spoke Maori or not, you could love this song because the tune's so catchy and the beat's so infectious. Dalvanius called it "hobnail boots music". It has that party strum that speaks to working rural New Zealand and those space invader sounds which spoke to urban kids. He orchestrated it to reflect the DNA of the people and the time. You can try to dissect it but it's really alchemy.

2. Does your documentary show a "warts-and-all" version of Dalvanius Prime?

More a "full colour, high definition" version. Dalvanius was a juggernaut - compromise didn't exist in his vocabulary. But he was also a chess grand master - he always had another play. He knew white radio wasn't going to play Poi E, so what does he do? He takes his hat off, goes up the main street of Patea and asks everybody for a $100 donation to record the video. When he couldn't get it screened he went to Derek Fox at Te Karere News, who made the music video their whole three-minute bulletin. He saw everything with so much clarity. To have a vision that no one else can see and take others along with you - that's what great people do.


3. Why did he have so many chihuahuas?

He had about 10 at one time and this was before lap dogs were fashionable. This dude was not copying anyone - he came fully formed. As a 7-year-old, he was rounding up all the loose pets in Patea and staging circus performances as their grand MC. He'd have chickens squawking, a three-legged dog running through a wall of fire. He had big imagination and talent but also huge commitment and discipline - a winning combination.

4. You went to Patea to meet the people who knew him. Did you have any surprises?

What hit me is how present he still is there today - despite his death in 2002 he's still shoulder to shoulder with that community.

5. Family and friends gave you access to previously unseen footage. What was your favourite find?

The crown jewel of the film is the original tape cassette recording of Dalvanius and Ngoi Pewhairangi singing Poi E for the first time in a jam session at her kitchen table at Tokomaru Bay in 1982. His cousin had the cassette hiding in a sock drawer for 32 years. Hearing those voices from the past is eerie. Ngoi had written the lyrics but the paint's still wet on the song and you can hear them consolidating it together. He picks up his ukulele and goes, "How does that shift happen again?" and they let it rip one more time. It's so special.

6. Why did Dalvanius ask Ngoi Pewhairangi to write Poi E for him?

She'd written Prince Tui Teka's hit E Ipo which Dalvanius produced. Realising Maori language could get airplay was a lightbulb moment for him. The record company had allowed it because it had that big stanza in English; "My darling Missy, you are always on my mind ..." So he visited Ngoi in Tokomaru Bay to ask for a song to perform at the Patea kapa haka festival. Both towns - East Coast and West Coast - had lost their freezing works. When he saw how tall his whanau became when they performed that song and the crowd's response, he realised he could do something more with it. The fact a waiata could be the genesis for social change is so powerful. I think because the path was so organic and real it allowed for wider change to take place. All revolutions start as whispers in the kitchen.

7. How far have we come since Poi E?

One of the bittersweet aspects of this story is that we haven't had another Maori language song reach number one. The challenge has been laid down for this generation. We need to remember that MPs make legislation but it's artists who create change.

8. The film premieres during Matariki - the Maori New Year. Was that planned?

I wanted it to come out on Waitangi Day but it would've been a very different story because Chris Bourke sent me a two hour interview he'd done with Dalvanius that really changed the game. I also used two interviews Dalvanius did with Henare Te Ua as a young man in 1983 and in 1987 after he's masterminded a world tour. It's fitting the film comes out during Matariki - a time for remembering people who've passed and celebrating their contribution. Because it has taken several years to make, sadly some people instrumental to the production have passed away including Dalvanius' eldest brother and my own mentor Eruera Nia.

9. When did you learn te reo?

I grew up in Christchurch where there were limited opportunities to speak te reo. Dad was a musician in Billy TK's band. We spent a lot of time on the road and twice a year we'd drive up to Pukekohe to see whanau. Nana always told the best jokes in Maori. She'd really come alive when she was cracking jokes with her cousins. She was a big influence. I went back and lived with her for a couple of years while I was studying history at Auckland University.

10. Your first feature film Mt Zion was set in your Nana's house in Pukekohe. How much of you is in that story?

There's a lot of my father and cousins but what motivates the main character, Turei, is definitely my story. That question of, "How far would I go to pursue my dream?" I got Jim Moriarty's phone number and rang him so many times to beg him to let me into his theatre company. I was 18 when I got in and spent two years on the road performing at high schools, marae and prisons around the country including three months inside Paparoa and Arohata Women's Prisons helping "lifers" devise plays and songs to perform at the Christchurch Arts Festival. Celia Lashlie was the prison warden who made it happen.

11. Why did you decide to try directing?

As a male Maori actor, I found myself typecast in this role of leather-wearing guy with a beer in one hand. Then Don Selwyn came along with The Maori Merchant of Venice. To be in a Maori language film was culturally electric. A lot of relationships were forged - my wife Reikura and I played the leads. So our next project was a Maori Romeo and Juliet.

12. What was your greatest challenge in making the Poi E documentary?

Allowing Dalvanius' voice to tell the story instead of my own; allowing the past and present to sing together on the same page and getting all the various formats to mesh while allowing them to exist within their own time signature. It's a big responsibility to be honest. Fortunately his sister Barletta's first words after watching the film were "Yup, that's our story". I felt grateful and humbled.

• Poi E: The Story of Our Song premieres on July 14 at the Civic Theatre to open the NZ International Film Festival. Nationwide release August 4.