Delays expected as public servants strike

Thousands of Centrelink, Medicare and tax office workers have walked off the job in a 24-hour strike.

The Department of Human Services has warned of increased wait times and reduced staff numbers over Friday.

Public servants are angry over the elongated time it has taken to come to a new enterprise bargaining agreement with the federal government.

The Community and Public Sector Union says negotiations began in 2013, with no agreement reached.

"These people are trying to support their families without a pay rise for three years," CPSU National Secretary Nadine Flood said in a statement.

"These workers are prepared to compromise but they're absolutely determined to get a decent outcome."

The all-day strike involves staff across agencies including Human Services, Medicare, Centrelink, Child Support, the Australian Tax Office, Defence, the Bureau of Meteorology, Agriculture and Water Resources.

A 24-hour strike was also held in August by the same agencies.

Meanwhile, some Australian Border Force staff are due to hold work stoppages from 8.30am on Friday for three hours.

The industial action linked to a pay dispute is likely to cause delays at international airports across the country.

Immigration Minister Peter Dutton has already publicly apologised to travellers for any disruptions.