UPDATED 5pm: According to RTE, 18 people were injured in the incident, with one person receiving serious but not life-threatening injuries.
UPDATED 4pm: The southbound lane of the N2 has reopened, according to gardai.
According to reports, one person remains trapped on the bus at present.
The N2 is closed north of Castleblayney at the Ballybay turn-off as emergency services deal with the crash there. Gardai advise using the Old N2 (R183) to divert away.
Southbound delays are building now on the Old N2 (R183) through Castleblayney itself.
Emergency services are currently at the scene of a road traffic collision which occurred on the N2 outside Castleblayney, Co. Monaghan today, involving a truck and a bus.
It is understood three persons have been taken to hospital with what have been described as "minor injuries". It is also understood that at least 30 people were on board the bus.
No further information is currently available regarding this matter as Gardaí are still at the scene.
Diversions are currently in place in the area
Further updates will follow.