The Local Link Bus has a service which runs every Tuesday and Friday from Clonaslee to Portlaoise via Mountmellick. 

The service collects at 09.45 from O’Connell Square and returns from Portlaoise at 12.15 on a Tuesday and 12.30 on a Friday.

The service does have to be booked 24 hours in advance by contacting the Local Link Bus on 05786 92168.

Link to timetables is below

https://locallinklaoisoffaly.ie/timetable/