The opposition's spokesperson for veterans' affairs has renewed his campaign to make the public holiday mandatory for government employees, by reversing a January 2023 public service determination that allows public servants to substitute their public holidays on Australia Day, the King's Birthday and Anzac Day for a different day off.

To substitute a gazetted public holiday for another day involves negotiation with a manager or agency head. There has also been controversy over whether Australia Day is observed by public servants or not on January 26.

In a statement, Mr Joyce said the public service policy over Anzac Day makes April 25 "optional and exchangeable" and he has again urged the more than 350,000 Commonwealth employees to ignore it to make sure next Thursday is a day of national remembrance.

"Of course, there has always been a requirement for some Commonwealth public servants to work on Anzac Day such as our Federal Police, Border Security, military and staff at the Australian War Memorial. However, these employees have always been required to work," Mr Joyce said in a statement.

Mr Joyce said, as he has complained about the policy for the past two years, it must be a deliberate move by Labor.

"Initially it had been assumed the federal government accidentally included Anzac Day when it made the same policy for other public holidays such as Australia Day and the King's Birthday. But the policy stands even after it was pointed out in Parliament. So, it wasn't an accident," he said.

The Canberra Times has sought comment from the Assistant Minister for the Public Service Patrick Gorman.

Mr Joyce used the issue of the Anzac Day public holiday to again criticise the Minister for Veterans' Affairs not being a cabinet position.

"This is another example of how veterans and their families are feeling the loss of their voice in Cabinet. Until Mr Albanese took office, the Minister for Veterans' Affairs sat at the Cabinet table. But not under Labor," he said.