Members of the Community and Public Sector Union, which represents non-media ABC staff including tech, HR and finance, walked off the job at 3pm on Wednesday to protest unmet pay bargaining demands.
Radio programming was the most significantly disrupted as hundreds of ABC employees downed tools across the country.
Singer-songwriter Bragg, who is known for his left-wing activism, treated workers gathering outside the broadcaster's Sydney headquarters to a rendition of union anthem Solidarity Forever.
The one-hour work stoppage followed similar, albeit smaller, industrial action earlier in the morning.
It comes a day after media workers union MEAA, who is also involved in negotiations, cancelled its own planned strike action after reaching an in-principle agreement with management.
As a result of the MEAA's cancellation, more than one thousand fewer staff participated in the walk-out than was initially expected.
CPSU ABC section secretary Sinddy Ealy said CPSU members were taking the action to send a message to management that they are unhappy with a "lack of respect" shown during the bargaining process.
"This is a reflection of the way ABC management have behaved throughout the entire process," Ms Ealy said in a statement.
"They have dug their heels in at every possible point, even when it was at the detriment of the ABC as a whole, and CPSU members have had enough."
Ms Ealy told AAP the union was looking for movement on two outstanding issues before they could come to an agreement - ensuring ABC workers would not be underpaid and that there is the possibility of career progression for workers at the top of their pay band.
The union has issues over buyout contracts used by the ABC, arguing that they do not properly compensate employees for overtime and penalties.
Ms Ealy praised the work of union members in negotiations, saying the offer is much better than its original state,
"In terms of next steps, the reality is we are so close on a lot of the matters," she said.
Earlier, MEAA media director Cassie Derrick heralded an agreement the union had come to with ABC management which landed employees an 11 per cent pay rise over three years plus a $1500 sign-on bonus.
"This has never been just about pay," Ms Derrick said.
"It's about ensuring a fair go at forging a career at the public broadcaster."
The ABC also agreed to conduct an audit into the gender and culturally-diverse pay gap, fix the buyout system and put in place career progression pathways.
In a company email on Tuesday evening, ABC managing director David Anderson said management would hold off on putting the offer to employees after unions requested additional time to raise issues with the proposal.
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