About 30 passengers have been evacuated and two flights diverted from Palmerston North airport after unattended luggage was left in the terminal.

Airport chief executive David Lanham said the passengers were being moved from the terminal to a nearby building with toilets and other facilities while police dealt with the situation.

Police say they are responding to an incident at Palmerston North City Airport that was reported around 1.30pm.

"The terminal has been evacuated as a precaution while inquiries into the circumstances are made."

Two incoming flights from Christchurch and Auckland have been diverted to Wellington and two flights scheduled to depart to the same cities before 4pm have been canceled.