Port Lyttelton says it will have to borrow money to fix its wharves because of a dispute with its insurer.
At its annual meeting in Christchurch on Thursday, the company told shareholders that Vero is refusing to pay $20 million to cover the cost of earthquake repairs.
The port says the amount has risen from $11 million to $20 million since August and legal action against Vero is an option.
It sustained substantial damage in the three major quakes.
Despite that, the port doubled its annual profit to more than $24 million due to more cargo passing over its wharves.
When adjusted for the impact of the earthquakes, this amount fell to just over $12 million.