The arrest comes after a 2- year police operation into the theft, which allegedly occurred after a $10 million overdraft facility was mistakenly loaded into Gao's business account.
Yesterday, police said he was stopped by a Hong Kong border patrol as he was crossing into Hong Kong from China at Lok Ma Chau.
He was subsequently arrested on a warrant relating to New Zealand theft and money-laundering charges.
Police allege he transferred $6,782,000 of the misdirected money into other accounts, after which the couple left New Zealand for Hong Kong - Gao on April 29, 2009, and Hurring on May 3.
The error was discovered on May 5 and about half the money was recovered from New Zealand accounts, leaving $3,872,000 missing.
Detective Inspector Mark Loper, of Rotorua, said the investigation had been "very active" and involved police from New Zealand, China and Hong Kong.
"There has been a significant amount of work under way behind the scenes - but for obvious reasons we haven't been in a position to discuss it," he said.
"The arrest in Hong Kong reinforces the determination and tenacity of police and our investigation team ..."
Mr Loper said Gao would be given the opportunity to return to New Zealand voluntarily. If he refused, it was likely police would begin extradition proceedings.
Hurring is to stand trial next year on charges of theft and international money-laundering to the value of more than $230,000.
In August, it was revealed that Hurring gave birth to a boy while in China and had to return home because of passport issues. It is understood she and Gao conceived their son after fleeing New Zealand.
Last night, Westpac Bank declined to comment on the arrest. "It's really a police issue," spokesman Chris Mirams said.
