Firefighters have cleaned up a substance at Christchurch's International Airport.

Fire Service shift manager Brent Dunn said a small quantity of white powder, believed to have come from a capsule, was found in the departures area.

He said it had now been put into a small bag and would be disposed of by the fire service.

Flights appeared to be arriving and departing as usual this morning, according to flight information posted on the airport's website.