New public transport cancellations have prompted calls for an urgent rollout of rapid COVID-19 testing for drivers and staff.
Melbourne's Yarra Trams put dozens of staff into isolation on Friday much like V/Line, which recently grappled with more than 300 staff being orders to stay home.
It caused major disruptions across the state including to Bendigo services.
V/Line returned to full service again early last week when enough staff ended isolation.
Victoria's opposition says too many people rely on trams, trains and buses for rapid testing to be ignored.
"Rapid testing for drivers and public transport staff will ensure we can catch outbreaks before they spread, shadow public transport minister Steph Ryan said.
The government will continue to work closely with the Department of Health, a spokesperson said.
"We have a number of initiatives in place to ensure our public transport network is clean and safe," they said.
The government is currently making a number of changes because of the delta variant including including reducing the number of overnight stays for conductors doing long-distance shifts which has now been suspended entirely for both drivers and conductors.
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