Bus drivers in Auckland are taking further action against their work conditions and pay - from 4am tomorrow some will refuse to handle cash.

More than 100 FIRST Union members from Howick and Eastern Buses are taking a stand, amid fears their overtime and weekend pay rates will decrease.

Bus organiser Rudd Hughes said they'll be refusing to accept cash from passengers, but passengers will still be able to travel to their destinations.

"Howick and Eastern are currently in the process of trying to cut the wages of the workers there, so we're having to take this kind of action in order to get them back to the table to get them start bargaining".

In addition to this, NZ Bus has been ordered to pay $10,000 by the Employment Relations Authority for breaching consultation obligations with its unions.

It's found NZ Bus was in breach of its good faith obligations under the Employment Relations Act.

The ruling follows city-wide strike action taken by drivers in February.

FIRST Union Transport and Logistics Secretary Karl Andersen said the company introduced new rosters without properly consulting with drivers and their unions.

He said the rosters were unacceptable and allowed drivers to work up to 10 or 11 hours per day with only a 10-hour break between shifts.