WELLINGTON - International drug smuggling gangs are targeting elderly travelers, New Zealand Customs officers warned Wednesday after a 72-year-old US citizen was charged with importing millions of dollars of methamphetamine.

The US man appeared in an Auckland court Wednesday charged with importing 6.2 kg of methamphetamine with a street value of 3 million to 6 million NZ dollars ($2.49 million to $4.98 million) and was remanded in custody until March.

The man arrived in Auckland from Bangkok on December 28 and was arrested after customs officers searched his baggage and found the drugs concealed in the lining of his suitcase.

The case drew similarities with two separate arrests of US nationals, aged 70 and 55, for importing methamphetamine into Australia last week, said customs manager investigations Maurice O 'Brien.

Criminal syndicates appeared to be targeting older people to carry significant amounts of drugs across borders, O'Brien said in a statement.

"It's important the public is aware that such criminal operations exist and people who, either knowingly or unknowingly, carry these drugs end up bearing the full brunt of the law," he said.

A 68-year-old Auckland man was arrested in November last year after he arrived into New Zealand from Papua New Guinea carrying 1.5 kg of methamphetamine concealed inside two bags he had been given.

The maximum penalty for importing class A controlled drugs into New Zealand is life imprisonment.