The Regional Officer for Unite the Union has made a formal complaint over heavy-handed policing at the picket line.
Eric Holmes says the disagreements are over boundaries for the strikers, particularly in regard to stopping buses as they leave the depots.
Mr Holmes says the police have been largely brilliant over the past two days, but he has recieved a number of complaints from drviers.
Mr Holmes outlines what the issues are:
The Police say they're satisfied that the officer in question has done nothing wrong and acted correctly.
They add that Mr Holmes has been given a police contact but has chosen not to use it.