Mr Nalder, talking up the Perth Freight Link at a business breakfast last Wednesday, said there had been some confusion about a proposed outer harbour at Cockburn Sound.
He said the outer harbour had always been intended to be an overflow dock to run simultaneously with the one in Fremantle.
�I�m getting a bit confused as to whether opponents (of the freight link) think it�s an overflow or they think it�s the whole port shifting there,� Mr Nalder said.
�But on that basis, if you shifted everything out, I�ve said you would not be covering it with lawn.
�It would be high-density residential and commercial, and in some ways I am attracted to that idea.�
Mr Nalder said the Perth Freight Link could provide up to 20,000 people with freeway access to the major hospitals, Kwinana Freeway and the airport.
But the move is unlikely to happen and would take up to 25 years once funding for a harbour at Cockburn Sound was gained.