Train drivers are reportedly being encouraged by their colleagues to strike during the Melbourne Cup Carnival.
Metro Trains is investigating claims of bullying and harassment amid allegations staff are being pressured to refuse overtime or call in sick during the spring racing carnival, The Age reported.
The company has written a warning lettert them of imminent legal action if they choose to "illegally" strike.
"If an employee if found to be encouraging, organising or engaging in any sort of overtime ban... Metro will take action," the letter, obtained by The Age, said.
Vicotria's Rail, Tram and Bus union (RTBU) flatly denied the strike rumours.
"What rubbish," Marc Marotta, secretary of the RTBU, said.
Metro Trains have assured they will have enough staff to cope with the 160,000 people expected to use trains on Cup day.