Rejected by his previous owner, Mongolian Khan now carries the Melbourne Cup hopes of a horse-mad Chinese billionaire affectionately known as Mr Wolf.

Mongolian Khan has already delivered Lang Lin a rare Derby double as well as a Caulfield Cup and the businessman hopes the four-year-old can get him a Melbourne Cup.

The Manchurian entrepreneur with a penchant for exotic animals - he apparently really does have pet wolves - has dreamed of a Melbourne Cup win.

"He's been having this Melbourne Cup dream for quite a long time," Lang's interpreter relayed in a recent New Zealand television interview.

"And to run in the Melbourne Cup or to win the Melbourne Cup, he's thinking about that every day."

Lang, who made his fortune through the Chuanwangfu chain of restaurants, has spent $NZ11-12 million ($A10.3-11.2 million) buying more than 800 New Zealand horses in the past three years.

Most he flies on chartered planes to Mongolia for the Inner Mongolia Rider Horse Industry he founded in 2006.

But his most expensive purchase in the 2013 New Zealand ready-to-run sale in Karaka, Lang's first time at the auction, was left in New Zealand to target Derbys and Group One races.

"He wanted to get a stayer," said Graeme Forbes, who helps manage Lang's horses.

"It was just his love of the action. He's beautiful," he said of the attraction of the horse rejected by his previous owner.

Bred by Tasmanian Graeme McCulloch, Mongolian Khan has been sold three times.

McCulloch went into foal share with Coolmore Stud but bought him back for $A9000 as a weanling in 2012, before sending him to a New Zealand yearling sale where he fetched $NZ140,000 ($A130,900).

"He was bought by a Cambridge agent for a Hong Kong buyer who didn't like the horse and told him to get rid of it," trainer Murray Baker said.

The horse has now amassed eight wins from 13 starts and prize money of $3.87 million along with the title of NZ Horse of the Year.

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"I think he just enjoys being a racehorse," Baker said of the New Zealand horse of the year.

"We feel that he'll be best as an autumn four-year-old - hopefully a trip to Sydney."

After the Melbourne Cup, Forbes hopes to build Mongolian Khan's international profile to promote him as a stallion, though he says Lang fancies the Hong Kong Cup while Forbes is eyeing the Dubai Cup.

Baker, who won Sydney's richest race the $4 million Group One Queen Elizabeth Stakes with It's a Dundeel in 2014, has three other Lang horses, all two-year-olds.

"They haven't got racing yet. We don't want to spoil it, we mightn't be able to start them," he said.

"He wants stayers so we'll wait."

According to the Rider Horse website, Lang has successful venture in education, manufacturing and property development.

But horses are his "deep passion" and he has set up a racetrack in Korchin in Inner Mongolia even though betting is still illegal in China.

Lang is expected to bring a group of interested Chinese buyers to the mid-November New Zealand Bloodstock ready-to-run sale, where he bought Mongolian Khan.

"I guess he'll be buying a few more horses," Baker quipped after the Caulfield Cup win.