Ships using the wharf could only pick up a part load of logs because the shipping channel was not deep enough for ships to take a full load, he said.
Logs were trucked on SH88 for shipping from the deeper waters of Port Chalmers.
"It's the only deep-water port available to the primary sector in Otago and Southland."
Rail transport was available between the yard and the port, but the rail option lacked the flexibility the industry needed, he said.
Log prices were strong but began to "soften" in July.
A reason for the "softening" was the significant increase in the cost of shipping in the past year.
Consequently, big ships and the highway were "critical" in allowing the primary sector to export its goods more efficiently, he said.
Port Otago delivered its full-year results for the year ending June 30 last week.
The results revealed a record year during which 1.19 million tonnes of logs had been handled, up 0.89 million tonnes on the previous year.
$182 million worth of logs was exported.
Port Otago's log area: Port Chalmers, 4.6ha; Dunedin Bulk Port, 4.5ha.
In the report, Port Otago commercial manager Craig Usher said a $2.9 million investment this year doubled log capacity at the Dunedin Bulk Port area, which includes Leith wharf and the Fryatt St log yards.
Project aims included reducing the number of large truck-and-trailer units on SH88 and having a clean wharf in Port Chalmers with no dust and bark to cater for its cruise ship passengers and container terminal clients.
"While our plans see logs ultimately being shipped from the Dunedin Bulk Port, some customers are not convinced this is the way to proceed. Their main concern is around the upper harbour channel not being deep enough to complete a full on-deck vessel load for a single destination when needed."
The log customers at Port Chalmers were important to Port Otago, he said.
"We know some of them are concerned about the move. We will continue to work with them on the Dunedin Bulk Port solution."