Euthanasia campaigner Philip Nitschke was detained for an hour and questioned at Auckland airport in New Zealand, a news report said.
Dr Nitschke said he was in New Zealand to hold public meetings and to launch a euthanasia drug test kit in the country, and that on arrival, he and his partner were hand picked from the customs queue, ABC reported.
He says they were questioned and their luggage searched by officials.
"They made it clear they knew that we were coming and that they would be wanting to search everything," he said.
Dr Nitschke says customs were particularly interested in the drug kits he was carrying, which tests euthanasia drugs, but are not drugs themselves.
He says they do not contravene Australian or New Zealand law.
Nitschke held over drug kits in NZ (ABC)