Gardaí investigating a serious assault on a man at a house party in Co Monaghan over the weekend believe he may have been attacked a number of hours before they were contacted.

The victim, a married man with four children, sustained serious head injuries in a rented house in the village of Oram just outside Castleblayney at a party held to watch the Conor McGregor fight.

The 42-year-old is now in a critical condition in Beaumont Hospital, Dublin.

Detectives at Castleblayney have issued an appeal to all those who were at the party to come forward and speak to them.

They say they are satisfied they will identify all those who attended.

Gardaí were called to the house at around 9.30am yesterday but believe the assault could have taken place more than three hours earlier and that the man lay seriously injured in the house for some time before an ambulance was called.

Gardaí were contacted by the paramedics and are now conducting a criminal investigation.

At least ten men and women are known to have been at the party which was held in a rented house and gardaí have yet to speak to them all.

An incident room has been set up at Castleblayney Garda Station and anyone with information is asked to contact gardaí on 042-9747900.