Man charged after Syd bus driver sprayed

A 50-year-old man has been charged with assault after he allegedly used mouth spray to attack a Sydney bus driver who refused to let him onto his crowded vehicle.

The man became irate after he wasn't allowed on the bus despite two other passengers alighting at the same stop in Surry Hills last week.

After arguing for a minute the man sprays the driver in the face almost 10 times before running off, CCTV footage shows.

It was initially thought the driver on Thursday had been hit with capsicum spray but NSW Police now believe it was mouth spray.

After an investigation, the 50-year-old man was arrested in Newtown on Monday and charged with common assault.

He was granted conditional bail to appear at Downing Centre Local Court in mid-January.

The bus driver was treated at the scene by ambulance paramedics after he began having trouble breathing but didn't require further treatment.