$4.5m 'Rolls Royce' organ unveiled in Auckland

New Zealand's biggest musical instrument had its first play to the public in Auckland this morning.

The Holy Trinity Cathedral's old organ wore out a few years ago, so they've got a new one as part of a $4.5 million refurbishment.

Organist Philip Smith is in the driver's seat, and calls the organ "a Rolls Royce of the highest quality". 

Just like a new car, this brand new organ, the largest musical instrument in New Zealand, comes with all the bells and whistles. It has 5432 pipes - the largest, 10 metres long, the shortest, barely bigger than a finger.

It took three days simply to tune it. 

"Everything was hand crafted...That's why it took two years to build before it even got here," Mr Smith says.

Built in the UK, it arrived piece-by-piece before being installed at Auckland's Holy Trinity Cathedral.

Ahead of its official blessing on Sunday morning, Mr Smith has been taking time to give it a test drive.

"It does take a while to get used to," he says.

"I'm getting used to hearing the organ - is it speaking from this side? Is it speaking from that side? Is it speaking around the corner? I'm balancing it all out around the building."

It's played for the public at least seven times a week, which ramps up to nearly 20 by Christmas. But this mechanical masterpiece has plenty more gas in the tank. 

"It's just an instrument of quality that will last. And if it's not here in 400 or 500 years' time, I'll be really upset," Mr Smith laughed.