A 68-year-old man has been caught with $1.5 million of methamphetamine in his luggage after being tricked by Nigerian internet scammers.

The Aucklander has been charged with importing and possession of a Class-A drug for supply.

He lost tens of thousands of dollars over several years in an online fraud and went to Papua New Guinea last month in the belief he would be given a large sum of money as repayment.

The cash never arrived but he was again promised a large payment if he carried a laptop back to New Zealand. He was also showered with gifts during his five-day stay in Port Moresby. He could not fit them into his own luggage so his hosts gave him two extra bags to carry them back.

Customs officers at Auckland International Airport discovered 1.5kg of methamphetamine concealed inside the luggage he was given, which led to a five-week joint investigation with the Organised and Financial Crime Agency of New Zealand.

Two more caches of the Class-A drug, weighing 1.2kg, were found hidden in shoes.

The total amount seized in Operation Gatsby has a street value of $2.7 million. Detective Senior Sergeant Lloyd Schmid said a lot of the drugs had been sent here from the Philippines and Cameroon through the international mail system.

Ten people have been arrested and charged with the importation and possession of Class-A drugs for supply, which carries a maximum sentence of life imprisonment. One of the accused also faces charges over a cannabis growing house discovered during the police raids.

Mr Schmid said the leaders of the alleged drug ring were Nigerian expatriates based in Auckland and Woodville, near Palmerston North.

"This investigation demonstrates the New Zealand drug market is being targeted by organised crime syndicates from every corner of the globe."

The unusual Operation Gatsby case has prompted police warnings on the twin dangers of internet scams and luggage security.

Maurice O'Brien, the Customs investigations manager, said people travelling overseas should never carry bags that do not belong to them and "remain vigilant at all times in respect of their personal security and that of their luggage".

Sharon Armstrong has only recently returned to New Zealand after being arrested in April 2011 when 5kg of cocaine was found hidden in her luggage at Buenos Aires Airport.

The Wellington woman believed she was taking a secret business contract - not drugs - to London where she was to give it to a man she had been dating online for six months.

New Zealanders are also being targeted frequently by ever-changing online scams and tricked into sending thousands of dollars overseas.

Detective Senior Sergeant Aaron Pascoe, head of the Auckland financial crime unit, regularly deals with the victims of online scams.

He said victims who stop sending money are often contacted by criminals pretending to be law enforcement officers who tell them the money has been recovered and they should travel overseas to collect it.