More than $23 billion will be invested into state infrastructure, including $2.11 billion on three road projects to fix traffic congestion on the Kwinana Freeway, Treasurer Mike Nahan has announced in his first budget.

Dr Nahan has invested the state's money into delivering 16 new primary schools, three new high schools, new hospitals, fire stations, 123 buses and 22 new rail cars by 2018.

Road improvements, including $57.2 million to finish Aubin Grove train station and car park, $55.4 million to widen Kwinana Freeway southbound between Roe Highway and Armadale Road, have also been outlined for completion in the next four years.

Dr Nahan said he was working to bring the city alive with an investment of $1.77 billion towards building the Perth Stadium, a new WA Museum, Perth City Link and Elizabeth Quay.