An investigation is under way into the assault and false imprisonment of a man in Mountrath, Co Laois that left him "very, very shaken".

Gardaí say that the man, who works as a security guard at the Iarnród Éireann compound in Kilbricken, was assaulted by a group of men when he arrived for work in the early hours of 5 December.

It is believed that he was then locked in the boot of his car before the men escaped.

Gardaí believe that there were at least three male assailants.

The incident happened at around 5am.

An Iarnród Éireann spokesman said the security guard is "very, very shaken" after the incident.

Speaking on RTÉ's Drivetime, Barry Kenny said the man suffered a blow to the head in what was a "very distressing incident."

Mr Kenny said he understands that five or six men were involved in the incident and that a number of items were stolen.

He added that security has been stepped up at the site and some other site as a result of the incident.

An appeal for witnesses has been issued and anyone with information is asked to contact Portlaoise Garda Station on 057 8674100, the Garda Confidential Line on 1800 666 111 or any garda station.