A spokeswoman said there had been "great progress" on the Warrnambool line upgrade, with trenching for signalling upgrades underway in Camperdown, Winchelsea and Boorcan, and works set to begin on the Boorcan crossing loop in coming weeks.

"These works will help improve reliability and deliver a fifth weekday return service for passengers in Victoria's south-west, ahead of stage two of the upgrade getting underway to deliver long-awaited VLocity trains to the line for the first time," the spokeswoman said.

Information obtained from the state government revealed stage one of the upgrades, which includes the fifth weekday service, is expected to be complete in late 2021.

Construction contractor Downer is progressing trenching works for signalling upgrades along the line.

The 2.2km crossing loop at Boorcan will enable trains to pass each other at this point on the line and help services recover from unexpected delays more quickly.

Earlier this year, 12 level crossings were upgraded as part of the first stage of the project, delivering boom gates, flashing lights, bells and improved train detection technology to boost safety for road users and train passengers.

The Victorian Budget 2020/21 invested $260 million to deliver stage two of the Warrnambool Line Upgrade alongside the federal government, which will allow modern VLocity trains to travel on the line for the first time.

It is not yet known when the end of stage two will be complete and the fast trains will run on the line.

Earlier, Wednesday: The wait for an extra service on the Warrnambool train line goes on after it was not included in the 450 extra services announced across the state's transport network.

The state's Minister for Public Transport Ben Carroll announced on Tuesday an extra 170 regional services and 280 new metropolitan train services, which would be added to the network each week from January 31.

The changes will allow for 45 extra services each week for Geelong line passengers, but will not see the addition of the much-anticipated fifth daily service on the Warrnambool line.

The fifth week-day service has been touted by the state government since 2016 but there has been no details on when it will be implemented.

The additional service is expected to be a key outcome of the Warrnambool line upgrade, rather than a timetable shuffle like the one announced by the state government on Tuesday.

The Warrnambool line upgrade was announced by Premier Daniel Andrews more than three years ago, with a promise to allow for the fifth weekday return service between Warrnambool and Melbourne, as well as a new crossing loop at Boorcan and 12 new level crossings.

The federal and state governments announced in August that an additional $30 million was needed to complete the upgrades.

The governments initially pledged $114 million for the line but federal Wannon MP Dan Tehan said those costs were "revalued" by the state government leading to the increased commitment.

An additional $26.8 million will come from the federal government, with Victoria providing a further $3 million.

When Premier Daniel Andrews visited the Warrnambool train station in July 2017 he said the $114 million works would take 12-to-18 months, meaning it would be completed in 2019 at the earliest.

But Ms Allan told The Standard in January that the works were now expected to be completed by late 2021 and the high-speed VLocity carriages would not run on the line once the upgrades were finished.

Ms Allan said "the line was in much worse condition than what was initially anticipated".

The state government was contacted for comment.

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