Marmion Avenue between Butler and Yanchep will be widened to four lanes, as the State Government announced it would spend $23 million on the upgrade.

Transport Minister Rita Saffioti announced the current single lane 11km carriageway would be upgraded on Sunday.

The planned upgrade will widen Marmion Avenue from Butler to Yanchep. Credit:Google Maps

"We recognise the area is one of the fastest growing regions in Perth, and that is why we are committed to getting the access right with both road and rail," she said.

"We've seen the significant congestion in this area. The City of Wanneroo and member for Butler John Quigley have raised this issue over many years as there's been further development and further housing all the way through to Yanchep, and now it's a great pleasure to be able to make that commitment of $23 million."