Euthanasia advocate Dr Philip Nitschke says he will make a formal complaint against Customs after being held at Auckland International Airport until 2am yesterday while officials scrutinised his and his wife's luggage.
The Australian activist, who is known by the nickname Dr Death, said he had been investigated by Customs officials coming into New Zealand before, but the inspection had never been as "severe" as it was on his current visit.
Dr Nitschke said he arrived with his wife in Auckland at midnight on Sunday and their luggage were searched "in detail" for prohibited items.
He said officials told him they also needed to search all of the couple's digital property, which included examining all documents on computers and memory sticks.
Dr Nitschke, who is in New Zealand for two workshops on how to source and use legal and illegal drugs for euthanasia, said nothing objectionable was found by Customs.
"My wife is saying she's never coming back to New Zealand again," Dr Nitschke told APNZ.
"I don't like being singled out. It's almost as if the policy is to make your entry into the country as miserable as possible.
"Absolutely [I will think twice about flying to New Zealand again]. I think it will be a good idea to make a formal complaint. I will be talking to our Wellington lawyers later today."
Dr Nitschke said he was told by Customs officials that they were working "as fast as they could" but some of their equipment used to examine digital documents had not been working properly.
"Our lawyers in Wellington made it clear that they have certain rights. The question is when is the inspection becoming unreasonable," Dr Nitschke said.
He spoke to a crowd of more than 100 in Auckland last night and will present in Wellington tomorrow where his key topic will be how to use nitrogen for a "reliable, peaceful, legal and totally undetectable death at the time of their choosing".
Dr Nitschke launched the company Max Dog Brewing last year, which he says can legally buy and sell nitrogen for brewing beer.
Dr Nitschke said he had a lifelong passion for brewing beer but admitted the company also provided a loophole so the drug could be supplied to people who wanted to use it for euthanasia.
He said his current trip to New Zealand would also include visiting the Christchurch Beer Festival on Saturday as part of Max Dog Brewing.
"If you were just going to say that we're marketing this product [nitrogen] only to help people die, there would be possible objections to that," Dr Nitschke said.
"Certainly in Australia it's very clear the gas can be used for brewing. We make it very clear that you can use it for a peaceful death or you can use it for brewing.
"I suppose you can do it for both if you wanted to - you can brew and then at some point you could use it to end your life."
He said he was expecting a large audience at his Wellington meeting and there were many New Zealand members of his pro-euthanasia group Exit International.
A spokeswoman for Customs said no complaint had been received from Dr Nitschke.
"If we do [receive a complaint] it will be treated in accordance with our standard complaints process and fully investigated. We are unable to make any further comment at this time," she said.