A large container-lifting straddle crane tipped over about 3.45am on the Fergusson Wharf at Mechanics Bay.
The injured driver was taken to Auckland Hospital in a critical condition, where 1 NEWS understands he is gravely ill.
The Noelle container straddle carriers in use at Ports of Auckland are more than 12m tall, weigh about 60 tons and can carry about 60 tons of weight.
Ports of Auckland acting CEO Wayne Thompson said in a statement that “at this stage the cause of the incident is not known.
“Our primary concern is for the welfare of our colleague and we are doing everything we can to look after him and his whānau, friends and colleagues.”
The terminal is closed while an investigation is carried out by Worksafe, and Ports of Auckland says it will also investigate.
The Maritime Union of New Zealand has confirmed the man is a member, but declined to comment further.