The country's biggest port, Tauranga, has reported a weaker profit as cargo volumes fell but says it's had an improvement in the second half of the year.

Key numbers for the 12 months ended June compared with a year ago:

• Net profit $90.8m vs $117.1m
• Underlying profit $102.7m vs $117.8m (excludes $11.9m one off tax charge)
• Revenue $417.4m vs $420.9m
• Cargo (tonnes): 23.6m vs 24.7m
• Final dividend 8.7 cents per share vs 8.8 cps

The port's result was likened to the previous year's "game of two halves" performance.

Chief executive Leonard Sampson says there had been a lot of volatility with the first half of the year with reduced cargo volumes and continued disruption to shipping services.

"There was a lot of impact of vessel schedule changes and overstocking of domestic supply chains but in the second half we've seen a lot stronger volumes, especially for commodities like logs and kiwifruit."

He says less than a third of ships were arriving on time and disruption caused by the Red Sea conflict was affecting services around the world.

However, the slowing economy resulted in a 2.5 percent fall in container volumes, with overall import volumes down 13 percent, while export volumes rose marginally.

Leonard says the port had been resilient in the face of tough trading conditions because of its diversified cargo range, which he believed would continue into the new trading year.

Its various subsidiaries and investments including Northport at Whangārei, Primeport at Timaru, and the newly opened Ruakura Inland Port reported reduced earnings.

Waiting for port extension

Leonard says  the port was still waiting for a final decision from the Environment Court on the expansion of its container wharf and handling, which has been planned and under consideration for six years.

It has interim approval from the court but was waiting for a final decision before it would start the two- year work of extending its wharf and associated cargo handling and storage facilities.

The port had also applied for fast track approval of the extension project as an alternative way to get the development underway.

"This is nationally significant and we really do have a lack of resilient infrastructure in New Zealand and we have been six years at this and it's infrastructure that New Zealand desperately needs.

"It's cost us many millions in the consenting process to date but the more significant cost is the many millions and millions it's costing importers and exporters through lack of shipping capacity ... the cost to us is dwarfed by the cost to the New Zealand economy."