Income for the Port of Lyttelton was lower in the five months to November compared with the same period last year.
The port says although container volumes are relatively even, changes in cargo mix has resulted in a fall in revenue, while income has also been affected by higher spending on maintenance.
The port company is picking a half year profit of between $3.2 million - $3.5 million.
Volume is expected to increase in the second half of the year. A full year profit of between $9 million - $10 million is forecast.