Some commuters are in for a cheap day of travel around Sydney, with certain bus drivers wearing plain clothes and not accepting fares due to a dispute with their employers.
Busways drivers in areas including Blacktown, Penrith, Windsor, Gosford and Wyong.
According to the Transport Workers Union, the action could carry through the rest of the week, with a new deal currently being negotiated.
However, this negotiation process has already been underway for nearly a year.
The current action is an attempt to minimise impact on commuters.
"Our anger is definitely pointed towards this employer and the state government and we don't want to interfere with the community or put them offside," TWU state secretary Richard Olsen said.
"They have been with us for many years in our endeavours to get good enterprise agreements.
"We want to keep the community there. So, this action in not collecting fares, not wearing uniforms is the first part of our industrial action campaign."