Lyttelton Port attributes its loss of $10.1 million in the six months to December to the effects of the 4 September earthquake.
Wharf and harbour structure damage from the 7.1 quake is still being assessed, but the port has written down the value of its assets by $22.6 million.
Excluding the impact of that earthquake, the port made $6.1 million in the six months to December, an increase of 67% on the same period a year earlier.
Revenue rose 13% to $47 million as the port moved more containers, coal and other cargo across its wharves.
Services are gradually being returned following last month's 6.3 quake. Chief executive Peter Davie says rail services should be restored on Thurday and within a couple of weeks all parts of the port should be operating - though not as normal.
Mr Davie says the port has insurance for restoring its assets, along with business interruption insurance, and the company will soon start talks with its insurers about the 22 February earthquake.
Lyttelton Port will defer dividend payouts until it gets paid by its insurers.
