Firefighters are currently dealing with a large chemical spill at a freight yard in South Auckland.
Fire Service spokesman Jaron Phillips said 900 litres of a "toxic and corrosive" chemical used in preserving timber had spilt while containers were being shifted at the yard in Mangere.
Staff were called to the incident about 10.15pm.
At least 100kg of soda ash would be needed to neutralise the spill, Mr Phillips said.
No one had been injured and the spill was not threatening any residential properties.
One hazardous material unit was already at the scene, and another one was on its way, he said.