Customs officers have told a court how they spent hours probing and drilling into a sparkling bronze horse head statue, eventually pulling out 35 one- kilogram bricks of cocaine.

Their careful work led to New Zealand's biggest cocaine bust at an estimated street value of $14 million.

American Ronald Cook Senior, 56, and 44-year-old Augustini Suarez-Juarez of Mexcio were arrested less than two months after the examination of the horse head, which was encrusted with diamante and had been air freighted from Mexico.

They are on trial at the High Court of Auckland, having pleaded not guilty to possessing and supplying cocaine.

On Tuesday, New Zealand Customs officer Kirk Robinson described the intricate steps involved in discovering and then removing the cocaine from the statue in a way that allowed police to set up a high tech sting to catch the drug's traffickers.

He described first investigating the names and addresses on the horse head's consignment note, before asking a sniffer dog to check the package.

The officers then unwrapped the statue, drilling into its eye and base before eventually cutting it open and removing the 35 packages of cocaine, Mr Robinson said.

They then repacked the statue with 34 packages containing flour and one containing polystyrene, cocaine and a tracking device, before sending it on its way so it appeared to have not been interfered with, Crown prosecutor David Stevens earlier said.

He alleged Cook and Suarez-Juarez then flew into New Zealand on two occasions last May and June, first to move the horse head statue to an apartment and then to supply cocaine extracted from it.

Police monitored the two men's movements until the pair discovered the concealed tracking device while attempting to complete a drug deal at the Crown Plaza Auckland hotel, Mr Stevens said.

They pair then fled to Auckland Airport but were arrested before they could board a flight to Los Angeles, he said.

Earlier, their defence lawyers told the jury the heart of the trial rested on the fact of whether the two men actually knew whether there was cocaine inside the horse head or not.

"Do not assume that Mr Cook knew there was cocaine inside that horse's head," Cook's lawyer Sam Wimsett said.

"This is something that the Crown must prove beyond reasonable doubt."

The trial is set down for four weeks.