Container volumes fell 6.3 per cent to 880,781 TEU, compared to 939,680 for the previous year.
Car and light commercial vehicle volume was down 15.2 per cent to 216,356 units, compared with 255,252 last year.
Total bulk and break bulk volumes, including vehicles, were down 11.7 per cent to 5.8m tonnes.
Non-car bulk and break bulk volumes fell 9 per cent to 3.4m tonnes.
Chief executive Tony Gibson said Covid-19 had presented the ports with "some significant challenges, reducing volumes and revenue".
But the company had risen to those challenges and was well-placed for growth.
"A huge focus this year has been to keep our people safe from Covid-19.
"As expected, automating our container terminal while still running a full operation has presented some challenges, and these have been exacerbated by the Covid-19 lockdown.
"There have been some impacts on customers, particularly the trucking sector, and we are working closely with them to make the change to automation as smooth as possible."
Despite the Covid challenges the port company had made "excellent progress" on key master plan projects and was well-placed for future growth "once New Zealand emerges from the current downturn".
Multi-cargo operations continued to perform well, Gibson said.
Productivity was high during the lockdown and continued to be as a result of lower multi-cargo throughput, he said.
Car dwell time on the wharf fell to a record low 2.07 days from 2.42 days the previous year.