Bus and rail passengers could face transport disruption as staff may refuse to work in certain "flashpoints" because of an increased risk of assaults and anti-social behaviour, according to the National Bus and Rail Union.

NBRU General Secretary Dermot O'Leary has again written to Minister for Transport, Tourism and Sport Shane Ross and Minister for Justice Charlie Flanagan, urging them to accelerate moves to establish a dedicated Garda Public Transport Policing Division to deal with the problem.

Mr O'Leary wants a commitment that temporary measures will be put in place, including a significant garda presence across the transport network, pending statutory measures to establish the necessary dedicated Public Transport Policing resource.

Last night, a man was taken to hospital after an incident on a train in north Dublin, though it is understood his injuries were not life-threatening.

Another man was arrested in connection with the incident.

In his letters, Mr O'Leary cites "startling" figures that from January 2017 to June of this year, more than 1,000 incidents of anti-social behaviour were logged by Iarnród Éireann, with further incidents across the bus transport system.

He refers to the "alarming" increase in violent incidents on the public transport network, saying there are now so many, that they seem to be normalised and unreported.

Mr O'Leary stated: "It is no exaggeration to say that commuters and staff travelling and working on public transport are doing so in constant fear of either being attacked themselves, or witnessing various forms of anti-social behaviour, up to and including serious assault."

He said that the safety of commuters and staff must be paramount, and reiterated his warning that it may only be a matter of time before transport staff could be forced into undertaking their own review of potential preventative measures, including an assessment of service provision at certain times and locations.

Mr O'Leary said he was initially encouraged by a response from Minister Ross in June, when he pledged to consult with stakeholders with a view to conducting a review (with the Minister for Justice) of security measures to ensure safety of customers and staff.

However, he said that five months after that assurance, staff were still waking up to headlines of yet more "thuggery" on public transport services.

Mr O'Leary has also forwarded the correspondence to a number of Opposition politicians.

Responding to queries from RTÉ News, the Department of Transport, Tourism and Sport cautioned that any dedicated transport police to address anti-social behaviour would require additional resources and the allocation of such garda resources would be solely a matter for the Garda Commissioner and his team.

A department spokesperson noted that the vast majority of the 45.5 million passenger journeys on Iarnród Éireann in 2017 last year occurred without incident, but acknowledged that the issue of anti-social behaviour has come increasingly to the fore in recent months.

He said the safety of passengers and staff - including arrangements to deal with anti-social behaviour on the rail network - are matters for the operators in conjunction with An Garda Síochána as appropriate.

However, he added that the minister was concerned to ensure that the necessary arrangements are in place to ensure the safety of all passengers and staff travelling and working on our rail network.

He said Minister Ross has asked the department to to engage with Iarnród Éireann and the Railway Safety Advisory Council - which includes representatives from operators and trade unions - on the issue.

The views of Iarnród Éireann and the Railway Safety Advisory Council have now been received, and Minister Ross has written to Minister Flanagan seeking his views.

In a statement, the Department of Justice said this correspondence is under consideration and has been sent to An Garda Síochána for its views "given the allocation of garda resources, including the manner in which garda personnel are deployed, is solely a decision for the Garda Commissioner and his management team".

The department said that: "In terms of tackling this particular form of crime, garda management already engages extensively with transport operators and a range of regional and local operations have been put in place to address incidents and issues that have arisen at specific locations".

The statement added that Mr Flanagan "will continue to work with gardaí and with Minister Ross in relation to the specific issue of anti-social behaviour on our public transport systems."

A spokesperson for An Garda Síochána said that it works with all transport providers to prevent and detect anti-social behaviour and criminality to protect the travelling public and staff.