Key government services have been delayed after thousands of public servants walked off the job on Monday morning as part of a rolling campaign designed to break a two-year deadlock on pay negotiations.
The strike action, announced three weeks ago and led by the Community and Public Sector Union, will see delays for those seeking assistance with welfare payments and travelling at airports.
Staff at Medicare, Centrelink and the Tax Office launched 24-hour strike action on Monday morning with clients told to expected to lengthy delays given limited staff. 
Department of Human Services general manager Hank Jongen said the strike action would stretch the department's resources and punish those who relied on government support.
"Our advice to customers is - if you don't need to contact us urgently, consider delaying your visit or contacting us another time," he said.
"We are confident customers' payments will occur as usual and we will do our best to minimise disruptions to services.
"However, we may have reduced numbers of staff in service centres and on the phone and increased wait times on Monday."
Staff at the Department of Defence, the Bureau of Meteorology, the Department of Prime Minister and Cabinet and the Bureau of Statistics also launched strike action on Monday.
Air traffic controllers and technical staff employed by the Department of Defence walked off the job on Monday and are expected to do so again on Thursday.
"Further 24-hour stoppages will occur this Easter Thursday in support of striking Border Protection staff by Defence staff from RAAF Bases Williamtown and Richmond in NSW," a union official said.
"Staff feel that the same values that compel them to serve to promote Australia's security also compel them to resist the Australian Public Service Commissioner's hypocritical and Machiavellian bargaining policy, which is a disgrace championed by overpaid executives and politicians."
Strike action at the Australian Tax Office has been supported by the Australian Services Union; although representatives have warned only CPSU members are protected against adverse action under the Fair Work Act.
ASU tax branch secretary Jeff Lapidos said, "We certainly support the CPSU's right to take this industrial action.
"But we intend continuing our campaign for a much better offer from the commissioner and we are planning to take other industrial action that our leadership thinks will be more effective."
On Thursday, Immigration and Border Force workers will walk off the job at international airports for 24-hours - the day before Good Friday.
Staff will continue with a campaign of rolling airport stoppages for several weeks over the Easter school holidays and beyond will escalate the action.
Similar work stoppages were held by ABF and Immigration staff in   September at airports in Sydney, Brisbane, Perth, Adelaide, Darwin, Cairns, and the Gold Coast.
CPSU national secretary Nadine Flood said the strike action would have an impact on key services such as Medicare, Centrelink and airports.
"That's unfortunate, but two years into this dispute, these workers still face an attack on their family-friendly rights and other conditions of work," she said.
"The extent of this mess is underlined by the fact that after two years more than eight out of 10 people working in the public sector still don't have a new agreement."
A spokesman for Employment Minister Michaelia Cash said it was unfortunate the CPSU had resorted to strike action.
"This can cause harm to the public and involves a loss of pay for employees," he said.
"Instead of resorting to industrial action the CPSU would better serve the interests of their members if they were to genuinely negotiate in good faith."
Strike action proposed by the Community and Public Sector Union:
Monday:
     24-hour strike action at Medicare, Centrelink, Tax Office, Defence, the Bureau of Meteorology, the Department of Prime Minister and the Cabinet and the Australian Bureau of Statistics.    
Thursday:
     24-hour strike action at the Department of Immigration and Border Protection and Agriculture.    
Ongoing:
     Immigration and Border Protection staff will oversee several weeks of rolling stoppages at airports across the nation.