IMPORT cargo volume at America's major container ports is expected to hit its highest level in nearly a year in August as retailers stock up for Christmas, according to the Global Port Tracker report released by the National Retail Federation and Hackett Associates.

"Port and package-delivery labour negotiations that threatened the supply chain at the beginning of the summer have been resolved and retailers are now focused on preparing for the all-important holiday season," said NRF vice president Jonathan Gold.

"There are always supply challenges to be faced but holiday merchandise is flowing into the country, and we expect to see a smooth shipping season ahead of the winter holiday shopping season."

Labour and management at west coast ports reached a tentative contract agreement in June, a 13-day port strike in western Canada that affected some US retailers last month ended with a tentative agreement, and United Parcel Service and the Teamsters agreed on a tentative contract that avoided a potential August 1 strike.

The Canadian labour agreement was ratified, but the others are still going through their ratification processes.

Hackett Associates Founder Ben Hackett said double-digit year-on-year decreases in cargo volume this year have come even though consumer spending and US employment have increased.

"Dollar figures for international trade show imports remain in a year-on-year decline and cargo volume shows the same," Mr Hackett said. "The discrepancy between rising growth in sales and declining cargo volumes is happening because retailers are working their way through inventory built up over the last 12 to 18 months. Cargo growth should resume as inventories are depleted."

US ports covered by Global Port Tracker handled 1.83 million TEU in June, the latest month for which final numbers are available. That was down 5.2 per cent from May and down 18.7 per cent year on year. That brought the first half of 2023 to 10.5 million TEU, down 22 per cent from the first half of 2022.

Ports have not yet reported July numbers, but Global Port Tracker projected the month at 1.91 million TEU, down 12.7 per cent year on year. August is forecast at 2.03 million TEU, down 10.2 per cent year on year but the first month since last October to reach two million TEU.

September is forecast at 1.97 million TEU, down three per cent; October at 1.99 million TEU, down one per cent; November at 1.92 million TEU, up eight per cent for the first year-on-year increase since June 2022, and December also at 1.92 million TEU, up 10.7 per cent.

Those numbers would bring 2023 to 22.3 million TEU, down 12.8 per cent from last year. Imports for all of 2022 totalled 25.5 million TEU, down 1.2 per cent from the annual record of 25.8 million TEU set in 2021.

Global Port Tracker, which is produced for NRF by Hackett Associates, provides historical data and forecasts for the ports of Los Angeles/Long Beach, Oakland, Seattle and Tacoma on the west coast; New York/New Jersey, Port of Virginia, Charleston, Savannah, Port Everglades, Miami and Jacksonville on the east coast, and Houston on the Gulf Coast.