Dozens of assaults on public transport staff have prompted calls for better protection.

There have been more than 100 assaults on public transport staff in Victoria since the beginning of 2014.

Staff have reported being punched, kicked, spat on and even threatened with knives.

Unions and industry representatives says self-defence training, conflict resolution lessons, and longer sentences for violent offenders will help reduce the alarmingly rate of injury.

The sector has also called for the deployment of protective services officers on buses.

The bus industry is the latest to join the chorus, saying it will install driver security screens on Melbourne buses, in response to “the most serious issue confronting the Melbourne workforce at present”.

Alarmingly, 70 per cent of Melbourne’s 500 bus drivers report experiencing aggressive behaviour from a passenger at least once a month.

New research from the Bus Association of Victoria has found that the impact of an assault goes well beyond physical injury, leaving many drivers psychologically incapable of going back to work.

A new report, Prevention of Aggression to Bus Drivers, says “assaults on bus drivers by passengers had significant negative impact on individuals' mental health and wellbeing, the productivity of businesses and the overall reputation of the industry”.

Fairfax Media outlets say they have seen industry statistics showing there were “84 assaults on Metro staff between January 2014 and February 2015, 15 assaults on V/Line staff from December 2013 to January 2015 and 11 assaults on bus drivers”.

Rail Tram and Bus Union Victorian branch secretary Luba Grigorovitch told reporters that it is unacceptable that transport staff remain at risk of assault for simply doing their jobs.

“It is not okay to spit on, abuse or assault customer service officers who are simply doing their job,” Ms Grigorovitch said.

“Whether it is a station officer who informs you that the train is late or an authorised officer who asks to check your [ticket], you must treat these people with respect.”

The union has called for self-defence and conflict resolution training for staff, as well as first-aid training and increased video surveillance.

Bus Association Victoria chief executive Chris Lowe violence against staff must stop.

“It's got massive knock-on effects,” Mr Lowe said.

The association's report found that 63 per cent of drivers did not feel they had the support of their employer when reporting aggressive passengers.