Nearly $2 million of methamphetamine was switched with rock salt and a hidden tracking device in a covert sting on a drug deal held in a supermarket carpark.

A crime syndicate from Iran was targeted in the "controlled delivery" which led to the arrests of two Iranian nationals, as well as a Polish courier and a leading gang figure.

In April last year, Adam Tyniec flew from Dubai to Auckland Airport on Emirates flight EK406.

A Pole living in Spain, Tyniec was carrying a small grey hard-shell suitcase, which was x-rayed by Customs officials.

The scan revealed "inconsistencies" in the lower half of the suitcase and on closer inspection a false bottom was discovered.

A clear plastic bag with 1.9kg of methamphetamine - worth $1.9 million at street level - was found inside, and the 50-year-old agreed to co-operate with the law.

Customs and police switched the drugs with rock salt and an electronic tracking device.

Four days later, Tyniec was called by Yashar Ghasemi and told to take a taxi to the Countdown supermarket on Quay St in downtown Auckland.

Money and drugs exchanged hands; Tyniec was given just $1000.

The 33-year-old Ghasemi, who came to New Zealand as a refugee in 2004, returned to his car nearby.

Police began to monitor his phone calls and followed him to two drug deals at the supermarket, including one with an Auckland gang member.

Ghasemi was sentenced to 9 years in prison after pleading guilty to possession of the Class A drug for supply, as well as supplying methamphetamine. The senior King Cobra gang member was arrested and charged with possession.

Another Iranian, who cannot be named as he faces a second trial, has pleaded guilty to possession of methamphetamine for supply.

Tyniec also pleaded guilty to importing and possession of a Class A drug and was sentenced to 7 years in prison.

As Auckland detectives were investigating the Iranian syndicate, Malaysian police arrested nine Iranians and seized 70kg of the drug and $2.9 million in cash.

The Iranian syndicate was supplying methamphetamine to New Zealand, Malaysia, Japan, Indonesia and Australia.

Journey from Iran to New Zealand can be lucrative

Iran has emerged as a cheap source of P which can be bought for $5000 a kilogram and sold for $1 million at street level.

International crime syndicates are smuggling huge amounts of the drug to transit points such as Malaysia and Thailand, then using human "mules" to shift the packages to countries including Japan and New Zealand, where P commands a strong price.

Bought for as little as $5000 in Iran, a kilogram of methamphetamine can be sold in ounce bags (28.5g) for a total of nearly $500,000 at wholesale prices in New Zealand.

A kilogram of P is worth $1 million at street level.

Those huge profits can be moved around the world through a traditional Islamic money transfer scheme, called hawala, which police say makes it virtually impossible to trace money laundering.