Partial strike action from Waikato bus drivers has turned into a full blown lock out from their bosses

The company has opted to lock drivers out after receiving notice of partial strike action which would see 120 drivers refuse payment from passengers.

Go Bus claims it's a health and safety issue, saying it puts all other drivers at risk of verbal and physical assault if passengers think they're going to get a free ride ... and don't.

First Union's Jared Abbott says it's a joke.

He says the company has never cared about health and safety in the past...some of its drivers work 60 to 70 hour weeks.