Extra border protection staff have been brought in at Sydney Airport as a series of rolling strikes kicks off on the first day of the NSW school holidays.
The stoppages, set to continue for the next two weeks, are part of a long-running dispute between Department of Immigration and Border Protection staff and the federal government over employment conditions.
Fully-trained staff have been brought in from other parts of the department, a spokeswoman from the department said.
"We are making sure there are no gaps (on the roster)," she said.
Despite the extra rostering, delays are expected over the next fortnight and the department has urged travellers to arrive early.
There were no reports of delays at Sydney's international airport on Monday morning.
Staff have been fighting for three years to stop the removal of certain conditions, some involving dangerous or specialised work, the Community and Public Sector Union says.
"Our overwhelming preference remains to sit down and find a fair and sensible resolution but the Turnbull government has shown it is unwilling to do so," CPSU National Secretary Nadine Flood said.
The immigration department said the strike action "flies in the face" of their bargaining process given the CPSU was set to enter negotiations with staff over a new wage deal this week.
"It is unfortunate that the CPSU is taking this action, fully aware that it will cause potential disruption and delay to the public," it said in a statement.
"The planned strike action will serve only to disadvantage CPSU members, who have already lost in excess of $2 million in salary deductions as a result of participation in strike action."
