Pakenham services cancelled as Andrews Government rushes to finish $2.3 billion high capacity train network

Evening services on parts of the busy Pakenham line have been cancelled for much of this week, as officials race to get Melbourne's new high capacity trains on the track.

The $2.3 billion program is running months behind schedule, with the first of the new trains only recently allowed to leave the Pakenham East depot under its own power.

The train is required to complete 10,000 kilometres of testing on the suburban network, before being accepted into the Metro fleet.

But the government's contract with builder Evolution Rail requires the first 2,500 kilometres of tests be undertaken between the last service of the day, and the first service the following day.

That's prompted PTV to cancel services between Dandenong and Pakenham from just after 8pm each evening this week to maximise the test window.

Shadow Transport Minister David Davis said the introduction of the trains had been "a shambles".

"These new trains have been much delayed, much more than 12 months, and now we see the government trying to hopelessly scramble to catch up", he said.

Daniel Bowen from the Public Transport Users Association said the trains were desperately needed on the busy south-eastern corridor, but said the test disruption was "a shame".

"You would hope that they would confine the testing to after normal operating hours, so as not to disrupt passengers", he said.

"Normally on the train from Dandenong to Pakenham it's about half an hour, getting on the bus tonight it will take an hour, so it is a significant delay to passengers".

But Transport Infrastructure Minister Jacinta Allan apologised for the impact on passengers.

"The new trains have to go through a rigorous testing phase", she said.

"Our windows for getting in there and doing this sort of testing for the trains has become a little bit narrower as we've expanded our services for passengers across the metropolitan network".

The new trains are not expected to start taking passengers until the middle of next year.

Last week the Andrews government came under fire after it was revealed 93 trains a day on the Pakenham and Cranbourne lines would be slowed down from December, to help Metro meet the timetable.