Western Australian Premier Roger Cook has announced that Westport has received funding for Stage 4 of its detailed design. Westport is the State Government's planning program to move container trade from Fremantle to Kwinana, about 20 kilometers south.

The government will invest $273 million to progress Westport to project definition planning, signalling a major step forward for the project.  

The announcement coincides with release of the Westport Business Case Summary, which recommends a one-off transition of container trade to Kwinana by the late 2030s.  

The document indicates significant risk to the Western Australian economy from future constraints on container trade if Westport is not built before Fremantle hits capacity constraints.

The business case found inaction to address constraints on trade could cost the Western Australian economy $244 billion over coming decades – an average of $5 billion per year – driving significant increases in the costs of everyday household goods and for local businesses.

Under a moderate growth scenario, Fremantle Port is expected to reach its capacity of 1.4 million containers per year by 2040, or as early as the mid-2030s if higher volumes of trade eventuate, with the surrounding road and rail network become significantly constrained – meaning a new port needs to be built by the late 2030s, to enable a smooth transition.

If no action is taken and trade exceeds Fremantle Port's capacity, containers bound for Western Australia will need to be offloaded at east coast ports and transported back by road and rail, adding to costs and putting economic self-sufficiency at severe risk.

The business case also confirmed that the option to extend the life of Fremantle Port would still require Westport to be built less than 10 years later, costing Western Australian taxpayers an extra $2.2 billion.

On the back of strong population growth, container trade through Fremantle Port grew by nearly 6% last financial year, representing an increase of nearly 50,000 containers compared to the year before.

Western Australia's population is expected to grow to 3.6 million people by 2036, which will fuel further growth in demand for container trade.

The business case estimated government investment of $7.2 billion will be required to deliver the new container port.