Go Bus operations director Nigel Piper was angry at the inconvenience it had caused public transport users trying to get to work in Dunedin.
‘‘The first bus out of Port Chalmers was delayed because of that.
‘‘Neither bus could be used - not with broken windows. It's a safety issue.''
Mr Piper said the buses had been parked off-street overnight. It was not yet known what was used to smash the windows.
‘‘It's just senseless vandalism. It doesn't achieve anything. All it does is inconvenience a whole lot of people and it costs us money, both in repairing the windows, in time and getting replacement buses sorted. Whoever has done this will be No1 on the most unpopular list in Port Chalmers,'' he said.
Dunedin police are investigating the incident.
Mr Piper asked anyone who had information about the vandalism to contact Dunedin police.
