Half the trains in the Melbourne railway network are travelling with defective passenger doors, according to an assessment report issued on Monday by Transport Safety Victoria.

The transport group has identified as many as 187 Comeng trains that it said need immediate repair or replacement. The cost could exceed $10 million.

Transport Safety Victoria spokesman Alan Osborne said most of the trains cited in the report failed to meet the state's safety standards as the doors on the units can be forcibly opened even when coaches are moving fast.

Alarmed that the trains' current state could risk passengers' safety, Osborne told ABC his group immediately notified the State Department of Transport.

The group also noted that the number of trains identified as needing repairs represent a big chunk of the Melbourne fleet, underscoring the immediacy of the situation and the danger it poses to the riding public.

"I'm not saying there's a massive risk that has to be dealt with right now, but what I do want to see is some committed plans put in place for the future so that we know that these things are going to get upgraded at the next major overhaul of the Comeng fleet," Osborne was reported as saying by ABC.

Unfortunately, he added, "I'm not getting good noises from the Department of Transport that this is going to be funded in the next major overhaul."

Victorian Transport Minister Terry Mulder has denied that the Melbourne railway safety was out of the state government's radar and insisted that he has been aware of the trains' condition for weeks now.

Mulder clarified that majority of these "trains are due for a mid-life overhauls and throughout the course of that, we may well be able to do that work," referring to the repair works cited by Osborne.

The Transport Minister also assured that he will initiate new round of talks with Metro about the matter and stressed "it's a concern ... we face that situation and we're going to deal with it."