Trains on the line between Frankston and Mordialloc have been suspended because of the signal fault, with replacement buses organised.

A Metro spokeswoman said boom-gates were down in the Carrum area and that engineers were working to fix the problem.

The disruption appears to have had knock-on effects in other areas of the train network, with cancellations aorund 6pm on the Sandringham, Lilydale and Belgrave lines.

The line was also hit with delays earlier today as a result of an ill passenger at South Yarra who had to be treated by paramedics.

More to come