The Melbourne Metro Tunnel project will generate 2000 more jobs than previously anticipated with a new pre-cast concrete factory to be built in Melbourne's west.

The project is now expected to create 7000 jobs in total, Premier Daniel Andrews said on Sunday.

The new pre-cast concrete factory will be built in the western suburbs, which the government said would benefit former automotive workers from Geelong and Ballarat. The factory will produce concrete segments to line the two tunnels.

Another plant is expected to be established in regional Victoria.

Mr Andrews said thousands of panels would need to be made and put in place to form the tunnels and station boxes.  

The Andrews government has also committed to sourcing locally 88 per cent of all materials used to build the tunnels and underground stations, including 93 per cent local steel. 

The $11 billion Melbourne Metro Tunnel, which will be complete in 2026, will include five new underground stations.

The twin tunnels will run between Kensington and South Yarra, connecting the Sunbury and Cranbourne/Pakenham lines.

But Mr Andrews hinted at further major rail and road projects in future, saying "we know there's a lot of catching up to be done."

"There will need to be more absolutely," he said. "If we're given that great honour, we'll keep on delivering them."

Mr Andrews said expressions of interest for the fourth package of works would go out later this week.

Last week the state government announced Lendlease would lead a consortium to build the tunnel and five stations.

The government has also promised there will be "revitalised space" above ground at the stations.

About 65 per cent of the Melbourne Metro project is expected to be delivered by small and medium-sized businesses.