Travellers must declare to Customs if they are carrying cash of more than $10,000 (or the equivalent). Those who don't can commit an offence under anti-money laundering laws.
Yu, who had sought discharge without conviction, lost an appeal to the High Court last year.
Although Yu was granted leave to challenge this before the Court of Appeal, the appellate judges dismissed his bid this afternoon.
One issue in the appeal was whether someone could attempt to fail to declare to take money out of the country.
On Yu's argument it was not possible to charge someone for this.
But Justices Forrest Miller, John Fogarty and Kit Toogood were not convinced.
"We accept that there may be offences that by their nature cannot be attempted by omission. But this is not one of them. As we have already held, the offence is not one of pure omission. It also requires a positive act of the offender, because he or she must take the cash out of New Zealand," the trio said in their decision.
"There is every reason to admit the possibility of an attempt in circumstances such as those of Mr Yu's offence," they said.