Buses will replace trains between Sunshine and North Melbourne from Wednesday night.
Passengers on the Sunbury line are being warned of extended journey times while upgrade works take place from 8.30pm on Wednesday, February 8 to the last service in Sunday, February 12.
Replacement buses will be a combination of express and stopping all stations services, and will operate as often as every six minutes during weekday peak periods.
Passengers should allow an extra 30 minutes for the bus journey.
During this time, crews will switch on upgrades at power substations at Footscray, West Footscray and Tottenham and install signalling equipment that will control the bigger, better trains that will run on the line when the Metro Tunnel opens.
Passengers are encouraged to visit ptv.vic.gov.au/disruptions for more information and to plan their journey.
