Transport Minister Dean Nalder said a tunnel across the Swan River was scrapped when it was realised this would mean digging up to 26m underground, making it too difficult for trucks stacked with heavy containers to make the journey back to the surface.
�There�s a certain gradient you need to comply with to get the vehicles up and that meant we�d be swinging a tunnel up and around Leighton Beach-Port Beach to come back in,� he said.
�The cost of that has removed that from our consideration.�
Mr Nalder said Stirling Bridge would likely clog with normal commuter traffic within 15 years and he was looking to bring upgrades forward.
He said there were a number of designs on the table.
�Those things are currently being explored as we speak, as is the route for phase two,� he said.
�We have Main Roads staff and Treasury staff on the east coast with the Federal Government � all the discussions have been positive.�