WA treasurer to lobby farmers on port sale

WA Treasurer Mike Nahan is heading to the bush to try and convince farmers the Fremantle Port sale is a good move - and they'll hopefully pressure the Nats to accept it.

It is the last capital city port in Australia to be considered for privatisation, but the plan, which aims to help reduce the state's ballooning debt, has been shot down by the Nationals.

Dr Nahan concedes the party's opposition means the sale almost certainly won't be achieved in this term of government, but he wants to go to the March 2017 state election with a commitment from the Nationals to support it.

"We would prefer to have our alliance partners in hand with us," Dr Nahan told reporters.

He's starting his road trip in Northam on Tuesday night and says he's confident he can convince various lobby groups and individual farmers to get behind the proposal, then pressure the Nationals to do the same.

"The WA Farmers Federation, Pastoralists and Graziers Association, and the livestock exporters are all firmly on side with the sale because they can see the gains," the treasurer said.

"They recognise, generally, that in today's climate, we have to recycle assets - as they do with the farms - to invest in others."

Dr Nahan told an earlier briefing of port stakeholders that the key reasons the proposed sale was rejected by the Nationals - access and pricing arrangements - would be outlined in amended legislation to be introduced to parliament.

He also said construction of an outer harbour to deal with overflow from Fremantle Port did not need to start for 15 years, rejecting suggestions it should be under way now.

A report by Regional Development Australia leaked on the weekend said developing a new harbour at Kwinana was the most urgent infrastructure project requiring government intervention.

Dr Nahan, however, said local councils had dominated the RDA assessment and used old data suggesting Fremantle Port would reach capacity sooner than projected by the government.

"The need to build an outer harbour is some years off," he said.