IF you need to call Centrelink next week, you might want to avoid calling on Monday or Friday afternoon.
Industrial action is planned by the Community and Public Sector Union on December 4 and 9 and it may affect Centrelink, Medicare and Child Support services.
Department of Human Services general manager Hank Jongen said customer payments would not be affected.
"We are focused on making sure staff are available to help people who are in financial hardship and need immediate assistance," Mr Jongen said.
"So we're asking customers with non-urgent business to consider contacting the department another time."
Customers are being encouraged to use online services through their myGov account or the ExpressPlus apps.
"We appreciate the community's patience during this time and I reassure you we are working hard to minimise disruption to the services they need," Mr Jongen said.
The union has flagged further industrial action to be held later this month.
For further updates on the industrial action visit www.humanservices.gov.au/servicechanges