A suspected people smuggler has been caught at Auckland airport, but he can not be prosecuted in New Zealand and will be transferred to Malaysia.
Immigration New Zealand said staff checking flights out of Buenos Aires saw four people with Malaysian passports being returned home after being denied entry to Argentina.
Border Operations manager Karen Urwin said the four passengers were stopped by immigration officers in the transit area of Auckland airport.
They noticed their accents were inconsistent, and the names on their Malaysian passports did not match their ethnicity, she said.
An investigation found three of the four passports were false.
Ms Urwin said three of the passengers confessed they were Chinese nationals.
They claimed to have paid the fourth passenger to be smuggled into South America via New Zealand, she said.
"The result of this operation is a testament to the fantastic job carried out by our immigration staff in close consultation with Customs officers at the border every day.
"While New Zealand was not the target of the smuggling this time it could be a different story next time.''
The three Chinese nationals were returned to China last night after a search by Customs found their genuine passports in their baggage.
The alleged people smuggler was a Malaysian citizen who was travelling on a genuine passport, Immigration New Zealand said.
He can not be prosecuted under New Zealand law as he and the other passengers were not attempting to enter the country.
The man was being held at the airport ahead of a transfer back to Malaysia.