Passengers arriving at all major Australian airports should be prepared for delays on Friday as quarantine inspectors will walk off their job for four hours over stalled pay negotiations with the federal government, the Community and Public Sector Union (CPSU) warned on Wednesday. Stalled pay negotiations with the federal Department of Agriculture, Forestry and Fisheries (DAFF) have sparked the new round of industrial action, which will start from 6 a.m. (local time) on Friday. About 3,000 DAFF workers stopped work for two hours a week earlier. The industrial action is also expected to impact on other DAFF services including cargo inspections, the release of imported goods and x-ray screening of international mail. CPSU National Secretary Nadine Flood said the union would escalate its industrial action in coming weeks unless the government gives a better offer. \"Taking protected action is a last resort for DAFF staff but we have been driven to this by the lack of progress on negotiations, and the refusal of the federal government to offer a pay deal that will not leave staff worse off after three years,\" Flood said in a statement. \"Our members are committed to delivering essential services but they are not prepared to accept sub-standard agreements that devalue their work.\" The government has offered staff a 3-percent pay rise over three years, which the union said was below the headline inflation rate of 3.6 percent.