Ongoing industrial action will return to the Federal Court this week as staff walk off the job for the third time.
The main public service union has warned the Federal Court, Family Court, Federal Circuit Courts and the National Native Title Tribunal could see staff shortages until Friday as staff ramp up strike action.
Community and Public Sector Union deputy national president Rupert Evans said court staff had gone four years without a pay increase and faced cuts to workplace rights and conditions under EBA proposals.
During strikes at the start of November, court registries in Darwin, Adelaide and Melbourne were closed as workers walked off the job.
Two judges adjourned court hearings due to the industrial action.
"CPSU members in courts feel they have no other option but protected industrial action," Mr Evans said.
"Courts management refuses to hear workers' concerns about the cuts, they've been through mergers, job losses and more changes are planned.
"Staff have been put through the wringer and enough is enough."
Mr Evans said management was being inflexible in the negotiations and had refused to move to Fair Work conciliation.
"All federal public servants have struggled to get a fair deal under the Turnbull government's harsh bargaining policy, but in other agencies across the APS we have managed to get the fairest deals possible while fighting off cuts to rights and conditions," he said.
"Not so in courts. Management there is doing everything in their power to treat courts workers like poor cousins. That's why staff are taking this unprecedented industrial action."
The union restated calls for Attorney-General George Brandis to step in.
Staff are negotiating a single agreement after the Federal Court of Australia's merger of administration with the Family Court and Federal Circuit Court last year.
Court employees responded with a 90 per cent "no" vote against a June proposal offering them half the wage rises being paid to their counterparts in other departments and agencies.
Court staff were offered a new deal with an average pay rise of 1 per cent for each of the proposed agreement's three years, cuts to conditions and entitlements and, for some, a longer working week.
This month a spokesman for Senator Brandis said the federal courts were responsible for their own operation and management, including enterprise bargaining matters.