Travellers flying to the United States and London are being warned to allow more time at the airport for additional security screening, including shoe x-rays at the boarding gate.
Aviation officials yesterday added a second tier of security at Auckland Airport in response to the latest terrorism threat to airlines.
Hand luggage on flights to London has been restricted to essential personal items carried in plastic bags, and no fluids except baby milk can be taken on flights to the US.
Cabin bags will be screened at the usual Customs checkpoint, then x-rayed again and searched at the aircraft gate.
Any prohibited items missed by the first screen will be confiscated.
Aviation Security Service general manager Mark Everitt said booths would be provided for people to remove their shoes for x-ray.
"I want to see minimal intervention with passengers, but at the same time we're not going to compromise security, so it's a matter of striking that balance."
The measures have been requested by the US Department of Homeland Security, and include a ban on carrying duty-free purchases on to planes.
Regency Duty Free would not comment on the impact that would have on business.
Peter Allard from DFS said he did not believe the liquids ban would stay in place for an extended period.
Flights to Asia and transtasman routes are not affected by the rules.
Qantas and Air New Zealand asked passengers to allow extra time to check in.
"Continuing flight delays are likely due to these increased security measures, and customers are advised to plan to arrive for their flight earlier than usual because it is likely checking in could take longer than normal," Air NZ said in a statement.
Flights to San Francisco, Los Angeles and London last night were expected to leave on time. Auckland-bound NZ1 left Heathrow early yesterday after being delayed.
Prime Minister Helen Clark said she had been briefed by British officials on the terrorist threat but she would not discuss details. She said the disruption could last some time.
New Zealanders in Britain are being advised to be extra vigilant on public transport.