An apartment building on Hobson St that houses a childcare centre was evacuated this morning after a fire in an air conditioning unit on the sixth floor.

A Fire and Emergency spokeswoman said a call came in about the fire at 11.38am and eight fire trucks attended.

"The fire has been extinguished and a fire investigator has been requested to attend," she said.

The building, which houses Auckland's Best Childcare Centre, has been fully evacuated.

There are no reports of injuries.