ABC staff and union representatives have urged the managing director, Hugh Marks, to retract “utterly offensive” comments after he said staff had treated taking industrial action as “a bit of a game”.

Marks made the comments just hours before the end of the 24-hour strike that saw more than 2,000 staff members walk off the job on Wednesday.

ABC staff ended their strike at 11am on Thursday but regular programming on its radio and TV broadcast networks took some time to return. News bulletins had returned to all ABC radio stations by 11.45am on Thursday. ABC News Channel continued to broadcast BBC News and prerecorded programs into the afternoon.

Speaking to Thursday’s fill-in breakfast host, ABC 702 manager Nick Lowther, on Thursday morning, Marks said while he was not aware of any future planned strikes, he was sure that staff would continue to engage in smaller forms of protected industrial action.

“There are little things like email, you know, changes in Teams usage, and to the extent, Nick, sometimes it feels like a bit of a game to me. And I don’t think this is a game. I think this is really serious,” Marks said. “And I think both sides need to say, you know what, the audience comes first and we need to stop playing games and focus on that and get to an outcome.

“At the end of the day, the people that are suffering are our audiences. So, you know, if they want the audiences to suffer more, of course it’s their right to take protected industrial action. That’s their right and we should respect that. Respect, I think, is a really important thing when you get into these discussions.”

The strike action was the first at the broadcaster in 20 years, taken by members of the journalists’ union, the Media, Entertainment and Arts Alliance (MEAA), and the non-journalists’ Community and Public Sector Union (CPSU), which represents staff in technology and control systems.

The action forced ABC services across TV, radio and digital to broadcast from the BBC News channel and run repeats and pre-recorded local programs.

ABC journalist Michael Slezak, co-chair of the MEAA ABC national house committee, said it was “utterly offensive” to suggest staff saw taking industrial action as a game.

“We have been at the table with management for nine months trying to reach an agreement that allows us to continue our work and deliver quality news and content to the audiences that we love,” Slezak told the Guardian.

“The claims that we have are all about creating a strong ABC with a bright future. The suggestion that ABC staff want to hurt audiences is beyond offensive. It’s outrageous, and he should retract those comments immediately.”

ABC staff have been protesting against what they say is a low pay offer that puts them behind inflation, unfair work conditions including the use of rolling and short-term contracts, and the broadcaster’s refusal to rule out replacing journalists with artificial intelligence.

Unions argued that the offer of a 10% total pay rise over three years – 3.5% in the first year and 3.25% in the second and third years – was too low and failed to address concerns about the staff appraisal process, career progression, night shift penalty rates and reproductive health leave. In January, Australia’s annual inflation rate was 3.8%.

Marks said staff costs were 60% of the ABC budget and any increase would mean job cuts. He denied the offer was below inflation because he said the last-minute offer of a $1,000 sweetener put staff ahead of inflation at 4.4%.

Marks has strongly refuted claims that ABC jobs are insecure and claimed more than 90% were permanent and the average tenure of an employee was more than 10 years. Marks claimed on Thursday the request for pay increases from staff was “unmanageable” and that “overindexing” payments to staff would put the ABC “in peril”.

Slezak, who is also president of the media section of MEAA, said Marks’ claims about job security at the ABC showed “he’s not listening to the staff”.

“What we are saying is that you cannot do fearless journalism if you’re fearing for your own job,” Slezak said. “That is just not conducive to quality news. He needs to come to the table and address these major issues.”

The ABC has lodged an application with the Fair Work Commission for assistance to resolve the dispute. The first hearing at the commission is scheduled for Monday 30 March.