A Cambodian man on trial in Napier today admitted possession of heroin for supply.

Sothea Kim, 32, changed his not guilty plea and admitted the offence when the High Court at Napier resumed today.

Kim is one of three men charged with possession for supply of 800g of heroin, estimated to have a street value of $12 million.

Kim and Nan Bou, 33, were yesterday discharged on a charge of importing the drug. One other man, Dy Lay, 43, still faces that charge.

Justice Young dismissed the importing charge at the conclusion of the Crown's case on Wednesday, but suppressed the information until mid-morning yesterday.

The court was told the men received 800g of near-pure heroin at a Napier house on January 8, after it was intercepted by an Auckland Customs official on its way from Phnom Penh.

The court was told that the heroin -- hidden inside video cassettes in two packages -- was replaced with glucose, bugged, and delivered to the house by a Customs official posing as a courier.

All three men were recorded on the microphone hidden in the packages after Kim accepted them and took them inside.

Bou went to the supermarket soon afterward, allegedly sent there to get plastic bags. He was arrested six hours after his return.

Lay, who has admitted being in Phnom Penh at the time the packages were posted, was yesterday singled out by the Crown as the driving force behind the operation, with Kim and Bou as accomplices.

Lay was unable to explain why his fingerprints were found in super-glue inside the cassettes, or what he meant by comments picked up via the hidden microphone.

Reading text of the conversation translated from Cambodian to English, it appeared Kim and Lay spilled some of the powder while opening the packages. At this time Lay was heard saying "the reason for the spill out is that when put it, the bags contain air ... we poked with needle, thus see holes to spill".

Earlier, he was recorded saying "we have capital again".

When asked by crown prosecutor Russell Collins why he might have said these things, he responded "I don't know".

Kim, who drove Lay down from Hamilton two days before the packages arrived, was observed waiting by the mailbox on January 7.

During questioning yesterday, he said he was instructed by Lay to receive the packages, and also to help open them once inside. His explanation for saying "victory" once back inside the house, was that he was happy for Lay because he knew Lay had been anxious to receive something in the post.

Kim said he obliged with helping open the packages, but became scared when he saw the white powder because he understood it to be heroin.

Bou's lawyer, Derek Quilliam, maintained that his client was unaware of what the packages contained.

Defence lawyers were summing up this morning, with the jury retiring this afternoon to begin their deliberations.