Public servants at Centrelink, Medicare and Child Support will up the stakes in their long-running fight with the Department of Human Services over pay and conditions. The agency’s staff could strike from 30 minutes to a day each time in the fresh wave of industrial action, which the Community and Public Sector Union has blamed on the DHS’ unwillingness to compromise in negotiations. But the department says the move will not change its offer in talks for a new enterprise agreement. CPSU national secretary Nadine Flood said it expected the industrial action, involving longer strike periods and held at a time of high demand for the department’s services, would cause significant disruption.