Prime Minister Bill English is playing down the "administrative error" that led to the US asking for Foreign Minister Murray McCully to be searched at Auckland Airport.
Mr McCully was on a list of "selectee searches" supplied by US authorities for the flight to Washington last month, the Aviation Security Office says.
The search took place despite the minister travelling on a diplomatic passport, RNZ reports.
He was not screened when he arrived in Washington.
The US embassy said the search was carried out in error.
A spokeswoman for the minister described it as an "administrative error".
Mr English told reporters he was sure no "negative intent" was involved.
"He may have been a bit surprised... I understand they think they made a mistake," he said.
Mr English said he had been searched while travelling on a diplomatic passport in other countries.