Western Australia is set to build a new shipping port in Kwinana, after an expansion of the existing Fremantle facility was ruled out by the government taskforce examining the state's freight needs.

Key points: A report ruled road and rail access remained a major problem for Fremantle

A report ruled road and rail access remained a major problem for Fremantle Five options for a new port at Kwinana are being considered

Five options for a new port at Kwinana are being considered But the Opposition says Roe 8 and 9 should have been examined

Five options for a new Kwinana container port will now be examined in greater detail, including one which would create a so-called "blue highway" linking Fremantle to the new outer harbour by sea.

But the taskforce, set up by the McGowan Government to push its outer harbour promise, dismissed the feasibility of relying purely on Fremantle for WA's freight needs into the future.

It ruled that even with the construction of the contentious Roe 8 highway extension and other proposed infrastructure improvements, difficulties with road and rail access into Fremantle Port would remain too significant.

"The high cumulative capital costs, concerns over the long-term sustainability and scalability and large levels of social impact, meant that the two stand-alone Fremantle options ... performed poorly," the report stated.

The report also talked up the benefits of moving the port from Fremantle, such as fewer freight vehicles in the western suburbs and the ability to redevelop land at the existing facility for other uses.

Ports Minister Alannah MacTiernan said the ruling that a new port would be needed in Kwinana was "unsurprising", saying there were "significant economic and social impediments" towards Fremantle options.

"The timing, scale and cost estimates of the new port will now be confirmed," Ms MacTiernan said.

Opposition attacks report

The State Opposition dismissed the findings as a "Mickey Mouse report", because Roe 8 and 9 were not factored into the technical studies which examined the various options.

"The report is fatally flawed," Liberal transport spokeswoman Libby Mettam said.

Kwinana has emerged as the leading contender for a new port to accommodate future freight needs in Perth. ( Supplied: Westport )

The most radical of the proposals is the "blue highway" shared port option, which would involve containers being moved from large ships onto smaller barges in Fremantle.

"The barges would then transport the containers directly down to the Kwinana port for offloading onto trucks," the report stated.

The taskforce said it would now undertake further investigations of all five options before again assessing cost and environmental and social impact, with a final recommendation to then be made to the Government.

A total of 23 options were assessed, with the bottom four all proposals involving Bunbury.

The report stated high operational and capital costs due to the distance from Perth, plus environmental concerns, made the idea of using the South West city as the site of the port unviable.

Port 'part of Fremantle's identity'

Fremantle Mayor Brad Pettitt said he wanted to ensure Fremantle remained a working port.

"Fremantle is going through a phase of rebuilding its economy and we don't want to see those kinds of things undermined, or even its very character," he said.

Fremantle Mayor Brad Pettit says Fremantle should be retained as a container port. ( Supplied: City of Fremantle )

"We've always been upfront in saying that we support an ongoing role for Fremantle as a port, but we acknowledge that there needs to be a limit on that, and we acknowledge that there needs to be a second harbour as well.

"We think retaining Fremantle as a working container port is an option that we would like to see really fully explored going forward.

"There's a huge amount of infrastructure on the north side, it's very much part of Fremantle's identity, and then having a second port down in Kwinana as well would make a lot of sense."