A private company has accused Dublin Bus of putting it out of business by engaging in unfair competition.
Circle Ran, which runs buses from Dublin city centre to Lucan and Celbridge, says it will be ceasing operations next week with the loss of 20 jobs.
It is accusing Dublin Bus of putting it out of business by saturating the route with a large number of public buses.
The company says it will refund 10,000 customers who bought annual smart cards.