Wayne Swan and Craig Emerson will give evidence as the full bench of the Fair Work Commission considers the long running Immigration Department pay dispute, dubbed the biggest industrial relations case since Qantas grounded its fleet in in 2011.
The former Labor ministers, former Immigration Department first assistant secretary Christopher Callanan, a group of academics and eight Community and Public Sector Union members working in the department will give evidence in the case, coming after a four year stalemate.
Lawyers for the department will give an opening address on Monday before the full bench of the commission in Canberra, ahead of the union's opening address on the second day of hearings on Friday.
The commission will consider the dispute and arbitrate the pay and conditions of more than 13,500 workers, coming more than a year after the commission halted industrial action by union members including strikes at Australia's international airports.
Immigration, set to become part of the massive Home Affairs department from next year, has offices in every Australian state and territory and in 53 locations around the world.
CPSU national secretary Nadine Flood said the Immigration Minister Peter Dutton, Minister Assisting the Prime Minister for the Public Service Michaelia Cash and the department, headed by hardline secretary Michael Pezzullo, continued to push for reductions to workers' existing allowances, rights and conditions and maintaining the longstanding wage freeze.
"The beginning of this landmark case in the Fair Work Commission marks a momentous day for thousands of our members working in Immigration and the Australian Border Force.
"Immigration and Border Force workers have now gone more than four years without a pay rise and yet Ministers Michaelia Cash and Peter Dutton are still pushing to cut real wages and for some even cut their take-home pay."
Ms Flood said the case had forced union members to take industrial action, including strikes at international airports.
"It's just over a year since those strikes ended, yet the department and ministers have shown no sign of coming to their senses and agreeing to a sensible outcome that recognises the critical roles DIBP staff play.
"Our members are responsible professionals who care deeply about their critical duties and just need a fair deal for their families.
"We didn't pick this fight but we will be arguing forcefully for an outcome that recognises the hardship this dispute has forced on CPSU members and their families, allowing workers to get on with their important work without their pay and workplace conditions going backwards."
Lawyers for Immigration made an aggressive move in June, scuttling some of the evidence in the union's case by arguing the material was covered by parliamentary privilege.
In a decision handed down on August 11 the commission said the same rules should apply to Immigration's case, knocking out material taken from budget papers and other government publications.
Ms Flood said the Turnbull government's public sector bargaining policy had been "disastrous".
"DIBP was the only agency even able to access arbitration through Fair Work despite years of battling, and these workers won't get a decision until 2018.
"This situation clearly shows we need to change the rules that favour aggressive employers over ordinary working people."
In August, an Immigration spokesman said delays in the long running case were "incredibly frustrating for the department and its staff."
Last week staff at The Australia Council for the Arts voted up their new enterprise agreement, following September's votes by Department of Human Services and Australian Curriculum, Assessment and Reporting Authority workers.