Australians are being warned to expect delays across Centrelink, Medicare and child support services for most of next week.
The Department of Human Services confirmed some staff will be taking industrial action next Monday, Wednesday and Friday.
General manager Hank Jongen said the strike - in response to the government's controversial automated debt recovery scheme - has the potential to disrupt telephone and face-to-face services.
Customer payments, however, will not be affected.
"Of course, anyone who needs to speak to us can phone or visit, they just need to know that this may take longer due to the industrial action," he said in a statement on Monday.
The department is asking people to use self-service options available through the myGov website and mobile apps.
Arrangements will be made to make sure staff will still be available to help those in financial hardship and who need immediate assistance.
"Our priority is to ensure that those most vulnerable, or with urgent queries, get the support they need," he said.
The public service union said workers were taking the industrial action over the "continuing damage" caused by senior management and the Turnbull government - not only over the Centrelink debt controversy but the stalled enterprise bargaining process.
CPSU national secretary Nadine Flood claims around 34,000 staff have gone more than three years without a pay rise.
