Peter Jackson’s “Lord Of The Rings” and “Hobbit” series have proved to be as precious to New Zealand’s economy as any magical ring as millions flock to the country for a glimpse of Middle Earth, making tourism the main driver of growth.

For years, coffers have been supplemented mainly by booming sales of dairy products from milk to infant formula.

But the sector is now struggling as oversupply and waning demand from key market China has seen the clamour for “white gold” dry up, fuelling fears the country was too reliant on one product.

But with breathtaking shots of sweeping landscapes and majestic mountains, the multiple Oscar-winning blockbusters shone the Hollywood spotlight on the country that has seen visitor numbers swell since the first film was released in 2001.

At its peak, New Zealand’s dairy industry shipped about NZ$17 billion ($12.1 billion) of dairy goods a year, accounting for almost a third of national exports.

Yet while that declined to NZ$12.2 billion in 2015/16, overall economic growth remains a healthy 3.6 percent, which the government says is the third best in the developed world.

And one reason for that is the slack has been taken up by the tourist industry, which Prime Minister John Key said was now helping underpin the national economy.

“Exceptional growth in the sector has generated around 6,600 new tourism jobs in the year to March 2016, and the industry now accounts for 20.7 percent of export earnings,” Key said this month.

Official data shows international tourists pumped NZ$14.5 billion into the economy last year and visitor numbers, currently 3.4 million, were set to double over the next seven years.

Tourism New Zealand (TNZ) chief executive Kevin Bowler said the growth had been phenomenal, thanks largely to the way the industry had leveraged the popularity of New Zealand’s film sector.

“Extremely successful Middle Earth campaigns and a deep focus on digital media helped drive significant growth in visitor numbers,” he said.

Wellywood game changer

The bulk of movie fans visiting New Zealand are attracted by Jackson’s two Middle Earth trilogies “Rings” and “Hobbit”, which have been described as marathon advertisements for the country’s rugged charms.

A survey showed 18 percent of international tourists last year cited “The Hobbit” as the reason they considered a trip to New Zealand.

Even Air New Zealand has got in on the act, employing Jackson to film a special Lord Of The Rings-themed safety video in 2012.

Almost 30 percent visited a Hobbit-related attraction during their stay, including Wellington’s Weta effects workshop or touring film locations.

TNZ is also using New Zealand-made films to promote tourism, with recent examples including campaigns around the children’s movie “Pete’s Dragon” and the upcoming science fiction feature “Ghost in the Shell”.

The capital, which styles itself “Wellywood”, has been among the chief beneficiaries of the film-related tourist surge kicked off by “Lord of the Rings”.

Wellington Regional Economic Development Agency spokesman Aaron Alexander said the city received global exposure from film premieres attended by stars of the movies and tens of thousands of enthusiastic fans.

“Middle Earth’s been fantastic for New Zealand and Wellington, putting us on the map for a whole new audience in a big way,” he said.

City officials are so keen on film tourism that they have committed NZ$150 million to a movie museum and conference centre, due to open in 2019.

The museum — a joint venture involving local council, Jackson and his movie industry associates — will house the director’s extensive movie memorabilia collection.

“It’s a dream product to take to market, it will be a world-class facility and the team at Weta have a proven track record,” Alexander said.

“It’s got the potential to be a game-changer in terms of triggering the decision to include Wellington on your itinerary.”

While exhibits at the museum will be updated to reflect new movies being made in New Zealand, Alexander said there was every chance tourists’ fascination with Jackson’s Middle Earth epics would endure.

“After all, people are still doing ‘Sound of Music’ tours in Salzburg 50 years down the track,” he said.