Police say ten passengers were on the TransPeak bus at the time of the collision in George's Road.
One man was briefly trapped on the top deck before he was rescued by firefighters.
Three women and three men were taken to hospital for treatment to cuts and bruises.
The bus driver was not injured.
– Sgt Danny Byrne
"It is only by sheer luck that no-one was seriously injured.
"If you were in the area at the time of the crash and witnessed the incident I would urge you to contact the police with any information."