A baby was among three people taken to hospital after being affected by capsicum spray used by protective services officers (PSOs) at a railway station in Melbourne's south-east on Friday evening.

Key points: Protective Services Officers monitor all of Melbourne's metropolitan train stations

Protective Services Officers monitor all of Melbourne's metropolitan train stations The baby and child were affected by second hand capsicum spray used on two men in Beaconsfield

The baby and child were affected by second hand capsicum spray used on two men in Beaconsfield New training programs for PSOs were introduced after concerns were raised about use of force in 2016

Police said PSOs at Beaconsfield Railway Station were forced to use the spray on two men after they became aggressive towards them around 10:00pm (AEDT).

Several onlookers were affected by secondary spray and were treated at the scene.

Three people — including a baby and a pre-school aged child — were taken to hospital for observation.

They have since been discharged.

The two men were interviewed and have been released pending further enquiries.

PSOs have patrolled Victoria's train stations since 2012, and in 2017 had their powers increased to include arresting people who had breached parole, search for illicit substances and response to incidents in and around train stations.

They work at all 212 metropolitan train stations in Melbourne to patrol on the train platforms and car parks.

The report found three "areas of risk" relating to PSO conduct, including "assault and excessive use of force, which represented 42 per cent of allegations examined by IBAC".

It recommended a review of training procedures regarding professional and ethical standards, along with communication and conflict resolution.

In response, Victoria Police introduced new training programs to improve "discretionary decision-making" and established a review system for notable incidents.

PSOs go through a similar application process and training as police members, though must achieve an entrance exam result "slightly less than the level" of an officer, according to Victoria Police.