As much as 35 kilograms of South American cocaine may have been shipped into the country by an admitted importer but has never been recovered, prosecutors have told a court.

Christchurch man Lee Dixon admitted to importing the drug in 2015, but argued it was no more than 100 grams ahead of his sentencing, according to a High Court ruling released this week.

But at a hearing to decide just how much he had brought in, the Crown said $US109,797 ($NZ151,794) Dixon transferred to Colombian accounts and given to an undercover officer in early 2015 would have been able to buy about 34.9 kilograms of the Class-A drug.

Dixon admitted he made contacts with drug dealers in Colombia and was found with a condom containing 97.5g of cocaine in his underpants at Auckland Airport in March 2014.

He was last year sentenced to seven months' home detention and 150 hours' community work, but was then charged with further importation offences.

Police grew suspicious of Dixon when he wired money to Colombian accounts in Hong Kong and Panama and then had a 10kg packaged labelled "submersible pump" delivered from Venezuela.

That package was never found and the Crown relied on the evidence of former US Drug Enforcement Administration agent Louis D'Ambrosio to estimate just how much Dixon could have received for his money.

In March 2015, he handed over $US70,000 to an undercover police officer in Hagley Park - the Crown arguing those who bought drugs did not usually pay for them until they had already been on-sold.

While Justice Nicholas Davidson concluded it was beyond reasonable doubt Dixon had imported at least 6kg, he said there wasn't enough proof to say how much more.

Justice Davidson said a striking feature of the case was that none of the drugs Dixon allegedly imported had ever been found by police.